Database Info

[Kernel] EFIDROID - Ultimate preboot enviroment! - Multiboot / Fastboot / UEFI

updated4/4/2017 (Still does not work on stock 5.0) - Removed due to it still not booting stock 5.0, and ALSO now breaks booting unpatched.
twrp 3.1 is broken
twrp 2.7 is broken
twrp 3.0.1 works
some/most custom roms work
Most official/stock do not.
EFIDROID - Official link
Developer: m11kkaa
DO NOT BUG THE AUTHOR ABOUT BUGS/FEATURES, THIS IS UNOFFICIAL.
Most custom roms appear to boot
Install:​
assumes on stock firmware (Custom roms must report the DEVICEID as hlte, hltetmo, hltespr or hltevzw. Ask your Rom maintainer to correct it or visit post #51)
assumes root and bootloader unlocked
For now "efidroid" on playstore is not configured for our device, so we will do this using our own server:
Download "EFIDROID" from the playstore
Download "TerminalEmulator" from the playstore (or use adb shell)
Download "SimpleHTTPServer" from the playstore
NEW UNTESTED - Removed
OLD Download EFIDROID_SERVER_FILES from View attachment EFIDROID_SERVER_FILES.zip
Open and extract the "device" and "ota" folder to the INTERNAL storage of your phone
Open SimpleHTTPServer (do not change default settings)
Open Terminal Emulator and enter: (make sure you didn't forget any spaces)
su
setprop efidroid.server_url "http://localhost:12345"
Now open efidroid, it should automatically connect. Now press the menu key in the top left corner and press install, then press the big install button.
Now create your slot, and reboot.
Use the vol +/- to navigate up or down, use the power button to select an option
Long press power button on internal rom/recovery to boot without efidroid
Reinstalling/Updating:
Download the new OTAPACKAGE file and extract to INTERNALSD, replace old device/ota folders
Clear EFIDROIDMANAGER cache/data
Run the SETPROP command (don't forget su)
Turn on SimpleHTTPserver
Open efidroid and click uninstall, and then click install (Or click reinstall)
MAKE SURE YOUR BUILD DATE NOW MATCHES THE UPDATED BUILD DATE
Uninstall:
if you hit the uninstall button, the app copies the contents of the UEFIESP back to the real partitions and deletes the partition_*.img files. It does not delete the UEFIESP directory or any of the multiboot directories because they may contain other important files.
flashing boot+recovery outside of EFIDroid's control(e.g. using stock's fastboot/odin flash, or using unpatched boot) is pretty much the same as uninstalling efidroid without deleting the partition_*img files.
All that means that you don't have to worry about any of that if you restores your boot+recovery partitions(either through the app or manually). If you want to free up some space you can delete the UEFIESP directory using a root file manager.
Bugs/Issues:
REPORT ERRORS/BUG ON GITHUB
"can't find tagloader for type -1" - your recovery/rom is not supported (like twrp 3)
Report errors: https://github.com/efidroid/projectmanagement/issues
What you must include:
Exact steps to reproduce the error
Give the exact error shown on screen
If its storage related:
Give the output of "cat /proc/1/mountinfo"
EMERGENCY :
If you find yourself frustrated and just wanting things back the way they were:
Download odin
Download twrp (get the md5/tar version for odin)
Turn off phone (pull battery)
boot to download mode by holding vol down and home and power
Start up odin and press the AP button and browse for the TWRP file. Press start to flash.
Reboot phone into twrp recovery (vol up + home + power), and restore your boot/recovery partitions.
EFIDROID has now been effectively disabled[/HIDE]
Help and info:
If you are familiar with adding touchscreen support please visit us!
Join us on Slack : http://join-efidroid.rhcloud.com/
Once joined: https://efidroid.slack.com/
EFIDROID G+ page : https://plus.google.com/communities/...43671219382368
[/CENTER]

Works on N9005 LTE ?

It looks pretty cool but I've got limited knowledge. My N9005 is on phronesis rom v4.1, IdleKernel v6.6.5 and all partitions converted to F2FS, will it work on this format as well :/

As long as it is a note 3 on msm8974 (sorry exynos) it should work.
File system support should be trivial. I used that same FS myself

Is this an actual GRUB loader for android?
If so am ashuming this means it's possible for UNIX install
i.e. Arch Linux as OS.......

Hmmm.... Windows RT on Note 3... ^^
What about ACPI? We might need this for WinRT

With all due respect, I think you've posted a how to post bit earlier. I'm a flashaholic & the wait for the zip is killing me

I didn't think the day would come.
As a pleb, I will follow this thread with great interest.

djmalik420 said:
With all due respect, I think you've posted a how to post bit earlier. I'm a flashaholic & the wait for the zip is killing me
Click to expand...
Click to collapse
lololol

Wonder if this is ever going to work Great concept though.

Fake ¿ ???
Only what i see its a bootanimation, in the Video from a "older and other"

The OP account is suspended so I guess something fishy is going on.

Guess we will wait and see

oh come on now. I got suspended for being rude to a well respected member of xda. And its not fake... Really? Anyways... I took my ban as a break and just started back with m1cha on getting the uefi part to work with the screen.
A few pointers: You still need devs to port each os, like windows, true linux ect.
This is just a multiboot. So many devices lack that, some had safestrap, or kexec ect, but all those methods had quirks or special rules, or depended on android. This loads before even the kernel.
Also, it will have many tools that a typical recovery has, so you may not even need to reboot into recovery to setup partitions, also aroma was ported, so maybe even installing roms/kernels too.
Also, there will be an efidroid server "store" where you can get tools and apps to run in efidroid. So devs can extend functionality. Also there will be an android installer to make everything easier.
Just think of this as a pimped out safestrap.

SaschaElble said:
oh come on now. I got suspended for being rude to a well respected member of xda. And its not fake... Really? Anyways... I took my ban as a break and just started back with m1cha on getting the uefi part to work with the screen.
A few pointers: You still need devs to port each os, like windows, true linux ect.
This is just a multiboot. So many devices lack that, some had safestrap, or kexec ect, but all those methods had quirks or special rules, or depended on android. This loads before even the kernel.
Also, it will have many tools that a typical recovery has, so you may not even need to reboot into recovery to setup partitions, also aroma was ported, so maybe even installing roms/kernels too.
Also, there will be an efidroid server "store" where you can get tools and apps to run in efidroid. So devs can extend functionality. Also there will be an android installer to make everything easier.
Just think of this as a pimped out safestrap.
Click to expand...
Click to collapse
It doesn't matter what negative comments you get because "Criticism Is The Key To Innovation" it's my personal quotation ...I've been visiting this thread since day one at minimum of three times a day hopping that you would have uploaded the zip...Make it quick buddy & keep up the good work :good:

We need a samsung expert. Getting the display to work in uefi is troublesome. DTSI and gcdb display experience is needed.

SaschaElble said:
We need a samsung expert. Getting the display to work in uefi is troublesome. DTSI and gcdb display experience is needed.
Click to expand...
Click to collapse
as far as my knowledge is concerned, Master @darkera13 is kinda expert you're looking for...I don't personally know him or his skills but people around note 3 forums praise his work very much

Is this Note 3 specific?
This is kinda an off topic question, but, just a few days ago i wanted to try Remix OS out in my PC, but noticed that there is no direct EFI support...just thinking if this thread would be any benefit for PC UEFI users trying to boot Android x86 directly through efi file.
sorry for the question, might be my knowledge limitation on the field...

Using a x64 cpu and grub or refind you can boot RemixOS, they have a uefi image on their site. (Thats what they said) Basically you really don't need efidroid for this, as it would only make it more complicated.

grub is exactly my problem...
thanks a lot for clarifying

zefieOS EFI Recovery System (Ares8) (Baytrail)

This is a developer level tool, aimed at advanced users
(see next post for releases)
My Ares8 allows you to boot from EFI by holding Home while powering on. This is good because fastboot blocks flashing the partition table and some partitions.
So I have created this mini OS (zefieOS) using Buildroot and a custom kernel I have been hacking together for the Ares8.
This system allows you to completely wipe and repartition your eMMC, restoring partition table and factory image.
A system like this will allow you to take greater risks with your tablet, especially useful for development.
If you wipe your eMMC to install Windows or Linux, you can easily restore to Android (if you have an Ares8, or use the upcoming backup feature).
It should be easy for developers to port to other boards by swapping out the kernel.
Buildroot custom files and configs are available on my GitHub. (may be needed for porting due to keymap overrides to navigate menus)
You can also check the "Projects" section on the GitHub to see what I am planning.
Video:
(QEMU Demo, but tested on my Ares8)
Features:
Restore compressed disk images (xz, bz2, gz)
Restore raw disk images
Restore TWRP raw eMMC images
Restore TWRP ext4 partititons, compressed and/or split
Secure Erase (Discard) entire eMMC and repartition
Copy log to USB
Entire OS is run from RAM Disk.
Shell access (keyboard required)
Dialog GUI navigable from device with keymap overrides
Restore without touching partition table
Multiple backup support
Source code available, easy to rebuild
Future:
To keep up on future plans, check out the "Projects" section on the GitHub
Disclaimer:
I have tested this on, and have successfully restored my Ares8 Gen2 (manufactured August 2016). However while this tool is being released on the assumption that it will work on all Ares8 devices, I will not be held responsible for any damage caused by this tool. This tool, in its current developer alpha state, is not meant to replace TWRP. It is meant to restore your tablet if it is otherwise useless to you, such as being in DnX mode (which means your ESP partition is corrupt or missing). Running this tool needlessly may cause damage, and this is solely your responsibility.

Releases can be found here:
https://archive.midnightchannel.net/zefie/linux/intel_baytrail_soc/zefieOS/
I am linking to a folder because I have decided to release zefieOS and the restore packs separately for easy updating.
To use, download the latest uploaded version of zefieOS, then download the Ares8 Gen2 restore pack.
More information can be found on the top of the page linked.
For now, I would not recommend this unless your tablet is in need of a FULL recovery (aka you are getting the DnX mode error), or if you are a developer interested in porting this to your device.
Developers should know the modular design of zefieOS is intended for easy porting to another device. This means you will not have to update your files 99% of the time when I release updates.
Eventually this will be a more user-friendly tool, but I wanted to release this functioning alpha release for those who may need to recover their Ares8 tablets.
I have successfully restored my Ares8 from DnX mode to a full working system using this tool.
I will continue to work on and improve zefieOS in my spare time.
Developers looking to port this to their devices should respond in this thread and I will help as much as I can.
Eventually there will be both a user guide as well as a developer guide.

[PX5][Android 10] Patched recovery

This is the Android 10 recovery image by HCT (version 10.3.1) patched to skip signature checking on .zip files
Tested on MTCE_LM (Eunavi). Use at your own risk
It can be flashed from a root shell (either adb or via terminal emulator) by performing the following steps
1. upload recovery via adb
Code:
adb push hct_recovery_patched.img /sdcard/
2. flash recovery
Code:
# backup current recovery
dd if=/dev/block/by-name/recovery of=/sdcard/recovery_backup.img
# write new recovery
dd if=/sdcard/hct_recovery_patched.img of=/dev/block/by-name/recovery
NOTE: If you do not disable the "flash_recovery" service in /init.rc, AND you have a stock kernel, recovery will be restored to the original version after rebooting.
There are 3 ways to avoid this:
- Flash magisk (or a modified kernel) while in recovery. The patch will then fail to apply and recovery won't be overwritten
- Disable "flash_recovery" by doing "adb remount" and editing /init.rc (comment out the following)
Code:
service flash_recovery /system/bin/install-recovery.sh
class main
oneshot
- Neuter the service by either:
- removing /system/bin/install-recovery.sh​- replacing /system/bin/install-recovery.sh with a dummy script​- removing /system/recovery-from-boot.p​

Woo-hoo, after hundreds of rubbish posts in the MTCD forums, we have a real development post!
Great work and thanks for sharing this, these forums need more like you.

Thanks for the kind comment!
I have to admit that it was frustrating to see the lack of information sharing on this forum, and the pervasive pay-per-use model.
I spent a lot of time just getting Android 10 installed (starting from Android 9), and i had to bring the head unit to my desk as working in the car was rather hard and all i achieved was a brick.
I unfortunately had to bring it back in the car now (can't sit on my desk forever) but, now that i figured out how to make bootable recoveries, i was wondering how hard it could be to have TWRP or at least a hassle-free recovery to install Android 10 from Android 9.
As a first step, this recovery makes it possible to install Magisk or other zip files without doing it manually within adb.
Cheers!

Your work is really good!
Thanks a lot for it.
Now you can also modify ROM's without signatur errors when installing.
Wouldn't it be good if we had an app like the ModInstaller ?
So a one click installation of the recovery without shell or adb.

I have now built an app.
And now need help.
Namely, in the app is the recovery and the script.
Unfortunately, the flash process is not started.
It always comes only the first message from the script.
The app is open source and the script and the recovery are in res/raw.
In the attach you will find the finished app and pictures.
If someone has a solution, he can write me or make a pull request on Github.
Source code:
GitHub - jamal2362/RK33XX-Custom-Recovery-Installer: Application for flashing custom recovery on Rockchip Android Head-Units.
Application for flashing custom recovery on Rockchip Android Head-Units. - GitHub - jamal2362/RK33XX-Custom-Recovery-Installer: Application for flashing custom recovery on Rockchip Android Head-Units.
github.com
The script:
RK33XX-Custom-Recovery-Installer/script at master · jamal2362/RK33XX-Custom-Recovery-Installer
Application for flashing custom recovery on Rockchip Android Head-Units. - RK33XX-Custom-Recovery-Installer/script at master · jamal2362/RK33XX-Custom-Recovery-Installer
github.com

First of all, congrats for the work!
DISCLAIMER:
I don't own ModInstaller, i have never bought a copy of it and i don't intend to do so.
Analysis is purely done from Youtube videos, open source code analysis and existing and openly available binary images.
I was working to figure out how to make a FLOSS alternative to ModInstaller.
The issues i found in all my attempts are the following:
- A6 recovery is the only one that can boot from SD Card (which can then be used to flash A9 -> A10 with the 2SD trick)
- (it took me a long time to pull these information together and unbrick my unit)​- The A6 recovery is unable to directly flash A10 RKAF/RKFW images (sdupdate.img) due to the code being too old
- a failure will be observed while writing super.img. This happens because the device needs to be repartitioned, and the A6 recovery is not doing it correctly​- A9 recovery is buggy. Booting it with no system installed will result in a black screen.
- it will only boot succesfully after being written by the A6 flash tool, which writes the "misc" partition with the recovery commands to run (the "hint" i get from this is that the misc partition is important)​- A10 recovery can't be loaded by the A6 recovery. I always got a black screen after flash. Is it a flash issue? is it an issue with the recovery itself? hard to know
Theory: maybe the recovery could be written over the kernel partition? ("boot")
This way, the recovery will always run after being flashed instead of requiring an explicit "enter recovery" trigger (buttons, misc partition, etc.)
Besides these experiments, in parallel, i did some bug fixing to this repository: https://github.com/liftoff-sr/rockchip-tool/commits/master (i'm "smx-smx")
That allows me to unpack nad repack "sdupdate.img" , "reduced recovery images" and "full IMG files".
With those tools. i tried to swap "recovery.img" in the A6 image, but i always got the black screen upon booting from SD.
Either A9/A10 breaks sdboot or the bootloader crashes before it gets there.
Since this also happens when being flashed, this could either be a bug in the flashing program or a bug in the boot stack (which fails to run recovery perhaps due to a dirty state of the internal flash). It's hard to know for sure without having a UART connection with the board.
BUT, we have an alternative, in the form of the recovery built-in ISP flash tool.
This is the code that reads "sdupdate.img" from the SD Card and flashes it
After reading the recovery source code, i realised that this code can only be triggered correctly when booting from the SD card.
It detects this state by reading /proc/cmdline and probing for specific values (https://github.com/rockchip-android...6f72b7d3123dab27135ac41d55029/sdboot.cpp#L206)
This means the bootloader can (and will) pass those arguments under specific conditions (https://github.com/rockchip-linux/u...c873f178c/arch/arm/mach-rockchip/board.c#L358)
If you check here https://github.com/rockchip-linux/u...3f178c/arch/arm/mach-rockchip/boot_mode.c#L47 you can see the magic word that needs to be written to the "misc" partition in order to trigger that code.
Note that, besides the well known "sdboot", "usbboot" is also possible.
I'm not sure if the ROM can physically boot from USB, but the bootloader and recovery do support (according to code) passing the flag to enable flashing from USB.
So, recapping, there are these ways we can try:
a - try to overwrite "boot" with "recovery" (but it might not work due to the partitioning layout, e.g. jumping from A6 -> A10)
- note: uboot might also need to be written when doing this.
b - making a modified "sdupdate.img" that flashes recovery on top of boot, and all the other core partitions like "misc", "uboot", "trust", "vbmeta"
c - writing "misc" from android in order to triggers the "rkfwupdate" mode
d - taking a dump of the first portion of the flash in various states (A6, A8, A9, A10), and having a "dd" that writes it back to the beginning of the flash (i suspect this is how ModInstaller does it)
Considering cases "b" and "c" depend on a recovery that can write them correctly (and the A6 one is buggy), this leaves us with "a" and "d"
Considering that ModInstaller does it in one shot, and doesn't seem to matter about the partitioning layout, i believe "d" might be the most viable option...
Using the "rockchip-tool" repository i linked from github, the partition table can be dumped from any .img file
You can observe "Image/parameter.txt" from the extracted firmware
This is the partition table from A6's recovery:
[email protected](uboot)
[email protected](trust)
[email protected](misc)
[email protected](resource)
[email protected](kernel)
[email protected](dtb)
[email protected](dtbo)
[email protected](vbmeta)
[email protected](boot)
[email protected](recovery)
[email protected](backup)
[email protected](security)
[email protected](cache)
[email protected](system)
[email protected](metadata)
[email protected](vendor)
[email protected](oem)
[email protected](frp)
[email protected](userdata)
And this is the partition table from A9's recovery
[email protected](uboot)
[email protected](trust)
[email protected](misc)
[email protected](resource)
[email protected](kernel)
[email protected](dtb)
[email protected](dtbo)
[email protected](vbmeta)
[email protected](boot)
[email protected](recovery)
[email protected](backup)
[email protected](security)
[email protected](cache)
[email protected](system)
[email protected](metadata)
[email protected](vendor)
[email protected](oem)
[email protected](frp)
[email protected](userdata)
Notice how uboot, trust, misc, resource, kernel, dtb, and others live in the same space. (2000, 4000, 6000, 8000, 10000, ...)
What we could do is create a raw blob that spans that address range, and "dd" it directly to /dev/mmcblk0 at the right offset.
So i would focus on converting recovery images to raw blobs, with recovery-as-kernel so it boots straight away on the first try.

Bump a real thread.

Is it possible to convert it to a file installed by SDDiskTool?

marchnz said:
Bump a real thread.
Click to expand...
Click to collapse
I created a flashing tool to flash recovery within Android, using Rockchip's own code: https://forum.xda-developers.com/t/...chip-firmware-flash-tool-for-android.4458299/

blala said:
I created a flashing tool to flash recovery within Android, using Rockchip's own code: https://forum.xda-developers.com/t/...chip-firmware-flash-tool-for-android.4458299/
Click to expand...
Click to collapse
This file hct_recovery.patched.img does not appear to be installed via rkupdate

sadaghiani said:
Is it possible to convert it to a file installed by SDDiskTool?
Click to expand...
Click to collapse
It needs to be converted, yes
I'll take a look this afternoon

blala said:
It needs to be converted, yes
I'll take a look this afternoon
Click to expand...
Click to collapse
Is it possible to create a boot image that includes moded recovery & magisk and moded kernel ?

If by image you mean firmware image then yes, it can be done with https://github.com/liftoff-sr/rockchip-tool
But what i would recommend is the modded recovery only, with the magisk .zip to use in Recovery
Otherwise you risk flashing a kernel that doesn't match with kernel modules or is otherwise not fully compatible with the installed system

blala said:
If by image you mean firmware image then yes, it can be done with https://github.com/liftoff-sr/rockchip-tool
But what i would recommend is the modded recovery only, with the magisk .zip to use in Recovery
Otherwise you risk flashing a kernel that doesn't match with kernel modules or is otherwise not fully compatible with the installed system
Click to expand...
Click to collapse
boot.img file included recovery+magisk+kernel

Flashing a boot.img (Kernel, for example) in an Android mobile phone via adb shell
Flashing a boot.img (Kernel, for example) in an Android mobile phone via adb shell - script.sh
gist.github.com

MTCD has separate boot and recovery partitions.
Perhaps you can adapt both recovery/kernel to be in the same image but the bootloader won't know about that (and will always boot from "recovery" partition)

Mobile/Android devices architecture

I'm having trouble understanding the architecture of mobile (and Android) devices. I compare it a lot to the design of PCs, laptops, etc, which I know quite well.
Here's my understanding on how PCs work when booting:
​The hardware has firmware stored in ROM (Read Only Memory). Actually, Flash memory is used nowadays, on which the stored content can of course be changed, unlike real ROM memories in the old days. Because the firmware is hardware-specific and its operation is very critical, its content is rarely updated or otherwise changed. Installing new firmware is called flashing. Firmware in a PC is most commonly BIOS or UEFI, the task of which is (briefly) to first run the POST tests, provide some interfaces and finally start the software in the mass storage. By mass storage, I mean memory separate from the firmware's Flash memory, which can also be Flash memory, such as an SSD disk, or a more traditional hard disk.​The BIOS (i.e. firmware) in the specified order (which first is the internal NVMe SSD or the external USB hard disk?) tries to load the software into the RAM memory for execution from mass storage MBR (Master Boot Record) part . Master boot record is a physical defined area in mass storage. Bootloader software is stored on this MBR part.​​When the bootloader (located on the MBR part) is loaded into RAM and run, it knows the contents of the end of the disk and starts the kernel from there.​​The kernel starts (in Linux) the init process, nowadays often Systemd, which starts the rest of the software.​--------------------
What kind of memories and storages are most commonly found in Android devices? One main memory (i.e. RAM)? One Flash memory for firmware (i.e ROM)? Another separate flash drive that acts as mass storage? Possibly SD card and USB stick as external mass storage?
What is firmware on Android devices?
What is the bootloader in (located in MBR part) on Android?
Linux is the kernel used by Android, which is started by the bootloader? After that, Android continues to boot, how?
A pile of terms, which I have ambiguities:
Bootloader; What's it like on Android? It is often characterized as hardware specific. So is it the case that the bootloader in Android is firmware? So in Android, the firmware runs the tasks of the PC world BIOS and bootloader (located in the MBR part), and then starts the Android located on the mass storage?
Recovery; What is this technically?
Android ROM; I can't understand this. As far as I know, Android is an operating system located mass storage, not Read-Only-Memory firmware.
Rooting; On a PC, we are used to the fact that the owner of the device has root rights. Is it just that the manufacturers have decided to set the default root password to some generated random string, and by default, the user only has access to the basic user account?
After the above has been answered, I would like someone to explain to me (separately) technically, starting from the hardware level (where and how), how do Android devices booting and work? Links to additional information are also welcome. hank you very much! If anyone can answer my questions, thank you very much!

Your questions should put you to shame.
Start reading yourself, building up your knowledge as you read.
Anyway, welcome to the forum. After a year of reading, you will laugh at your post.

ze7zez said:
Your questions should put you to shame.
Start reading yourself, building up your knowledge as you read.
Anyway, welcome to the forum. After a year of reading, you will laugh at your post.
Click to expand...
Click to collapse
I know my questions are stupid, but I'm impasse. It seems that there is much less information about designing for mobile devices than PCs. Could you link some articles on this? As the last article I read this, but it didn't help much, because I compare too much what I learned on PCs.

There are no stupid questions, there are only stupid answers.
Start with the basics based on information from google:
Architecture overview | Android Open Source Project
source.android.com

ze7zez said:
There are no stupid questions, there are only stupid answers.
Start with the basics based on information from google:
Architecture overview | Android Open Source Project
source.android.com
Click to expand...
Click to collapse
That is useful, but there is a reason why I asked about mobile/Android device design/architecture. Android itself is as far as I know (if I'm not mistaken) just an operating system, like the desktop operating systems Windows and Ubuntu, but mobile/Android devices are very different from PCs in terms of hardware and firmware. For example: https://www.quora.com/Is-there-anything-like-BIOS-in-mobiles-How-do-they-boot

How long is a huge ball of string?
No simple answer...
This is for those who are new to Android development and basically have NO understanding about the partition structure. I will give a high-level introductory explanation. PC GNU/Linux users: please note this is completely different from x86 (PC Linux) partition table. You will not come across partitions denoted as sda1, sda2, sdb1, sdb2, and so on. Instead, it will be structured as follows:
/boot
This is the partition that has all the data that is necessary for the phone to boot. It includes the kernel and the RAMDISK (these are the only components of the operating system that are stored in this partition. The remaining are stored in /System). Without this partition, the device will simply not be able to boot. Wiping this partition from recovery should only be done if absolutely required and once done, the device must NOT be rebooted before installing a new one, which can be done by installing a ROM that includes a /boot partition.
/system
This partition basically contains the entire operating system, except the kernel and the RAMDISK (as mentioned in /boot explanation). This includes the Android User Interface as well as all the system applications that come pre-installed on the device. Wiping this partition will remove Android from the device without rendering it unbootable, but you will still be able to boot into the /recovery partition to install a new ROM.
/recovery
The recovery partition can be considered as an alternative boot partition that lets you boot the device into a recovery console for performing advanced recovery and maintenance operations on it. Think of this like a proprietary recovery partition that PC companies put on prebuilt PCs. When you flash a custom recovery such as TWRP or CWM, you are overwriting this partition.
/data
Also called userdata, the data partition contains the user’s data – this is where your contacts, messages, settings and apps that you have installed go. Wiping this partition essentially performs a factory reset on your device, restoring it to the way it was when you first booted it, or the way it was after the last official or custom ROM installation. When you perform a wipe data/factory reset from recovery, it is this partition that you are wiping.
/cache
This is the partition where Android stores frequently accessed data and app components. Wiping the cache doesn’t effect your personal data but simply gets rid of the existing data there, which gets automatically rebuilt as you continue using the device.
/misc
This partition contains miscellaneous system settings in form of on/off switches. These settings may include CID (Carrier or Region ID), USB configuration and certain hardware settings etc. This is an important partition and if it is corrupt or missing, several of the device’s features will will not function normally.
/sdcard
This is not a partition on the internal memory of the device but rather the SD card. In terms of usage, this is your storage space to store your media, documents, downloads, pictures, videos, ROMs etc. on it. It is like the equivalent of the ' Users/[Username] ' folder in Windows and ' /home/~ ' folder in x86 Linux. Wiping it is perfectly safe as long as you backup all the data you require from it, to your computer first. Though several user-installed apps save their data and settings on the SD card and wiping this partition will make you lose all that data.
On devices with both an internal and an external SD card – devices like the Samsung Galaxy S and several tablets – the /sdcard partition is always used to refer to the internal SD card. For the external SD card – if present – an alternative partition is used, which differs from device to device. In case of Samsung Galaxy S series devices, it is /sdcard/sd while in many other devices, it is /sdcard2. Unlike /sdcard, no system or app data whatsoever is stored automatically on this external SD card and everything present on it has been added there by the user. You can safely wipe it after backing up any data from it that you need to save.
/sd-ext
This is not a standard Android partition, but has become popular in the custom ROM scene. It is basically an additional partition on your SD card that acts as the /data partition when used with certain ROMs that have special features called APP2SD+ or data2ext enabled. It is especially useful on devices with little internal memory allotted to the /data partition. Thus, users who want to install more programs than the internal memory allows can make this partition and use it with a custom ROM that supports this feature, to get additional storage for installing their apps. Wiping this partition is essentially the same as wiping the /data partition – you lose your contacts, SMS, market apps and settings.
/Boot (Is NOT viewable in Android)
/Recovery (Is NOT viewable in Android)
/Data (Userdata) (Is viewable in Android)
/Cache (Is viewable in Android)
/System (Is viewable in Android)
/Misc (Is NOT viewable in Android)
Ram
https://developer.android.com/topic/performance/memory-management
Understanding Firmware naming:
N986USQU1ATGM
N=Note
986U or F etc, the model of device
SQ, FX etc = CPU and model specific
U,S,E = Update, Security, Engineering, respectively
1,2,3,4,5 etc = bootloader revision (This is important! You cannot go to a previous revision)
A,B,C,D = Android version
T, U = Year (T=2020, U=2021 etc)
A,B,C etc = month (January A - December L)
1 - 9 and then A - Z =build compilation. This basically means how many builds there are in a month. They start at 1 and go to Z
So N986USQU1ATGM would be
N968-U-SQ-U-1-A-T-G-M
N968U (Note 20 Ultra Carrier version), SQ (Snapdragon), U (Update), 1 (Bootloader version), A (Build 10), T (2020), G (July), M (22nd build)
How to enter Download Mode:
Turn off the device.
Connect USB cable to your PC (Leave it disconnected from the phone)
Press and hold down the Volume Up and Volume Down buttons. While they are still pressed, plug in the USB cable into your phone.
The phone will go into download mode press volume up. In Odin you will see that phone is added.
Dirty Flash:
I would only do this if you are having to manually update to the newer firmware and would not do it if you are coming/going to U/U1 or from beta firmware or if you are on an old firmware. I'd also highly recommend doing a back up prior to the doing this
Load these into Odin
BL
AP
CP
HOME_CSC
Do NOT flash CSC or USERDATA, either of these WILL wipe your device
This is a "dirty flash" and these can sometimes cause issues. Keep in mind if things start going sideways and stuff starts not working right, your first step to a solution will be to wipe the device.
Tips on flashing U1 Firmware:
You will have to wipe, can NOT dirty Flash going between U and U1 firmware
Use the patched ODIN linked in post #2 or #3, Odin3_v3.13.3b (They are exactly the same)
Have an active US Carrier SIM installed to get carrier features
If you get your CSC Stuck on XAA/XAA/(Insert your carrier here), and can not get Carrier options back.
PIT files
https://ihax.io/samsung-pit-files-explained

plus_rlus said:
I know my questions are stupid, but I'm impasse. It seems that there is much less information about designing for mobile devices than PCs. Could you link some articles on this? As the last article I read this, but it didn't help much, because I compare too much what I learned on PCs.
Click to expand...
Click to collapse
The are no stupid questions.
Questions are asked when we do not understand something and want to learn.
There is nothing wrong or negative about asking questions.
Questions are a part of how we learn.
Cheers.

plus_rlus said:
<SNIP>
What kind of memories and storages are most commonly found in Android devices? One main memory (i.e. RAM)? One Flash memory for firmware (i.e ROM)? Another separate flash drive that acts as mass storage? Possibly SD card and USB stick as external mass storage?
What is firmware on Android devices?
What is the bootloader in (located in MBR part) on Android?
Linux is the kernel used by Android, which is started by the bootloader? After that, Android continues to boot, how?
A pile of terms, which I have ambiguities:
Bootloader; What's it like on Android? It is often characterized as hardware specific. So is it the case that the bootloader in Android is firmware? So in Android, the firmware runs the tasks of the PC world BIOS and bootloader (located in the MBR part), and then starts the Android located on the mass storage?
Recovery; What is this technically?
Android ROM; I can't understand this. As far as I know, Android is an operating system located mass storage, not Read-Only-Memory firmware.
Rooting; On a PC, we are used to the fact that the owner of the device has root rights. Is it just that the manufacturers have decided to set the default root password to some generated random string, and by default, the user only has access to the basic user account?
After the above has been answered, I would like someone to explain to me (separately) technically, starting from the hardware level (where and how), how do Android devices booting and work? Links to additional information are also welcome. hank you very much! If anyone can answer my questions, thank you very much!
Click to expand...
Click to collapse
Firmware is the hardware specific drivers, library files and other resources that are supplied by the manufacture(s) and are chipset specific.
The firmware is proprietary and normally closed source. Basically the parts that make the hardware work.
The bootloader is what actually boots the device.
This is supplied by the device manufacture(s) and is device specific.
It is separate from the system.​
Recovery is a mini Android environment.
- Factory (Stock) recoveries are restricted to the user but have unrestricted (root) access to the device.
- Custom recoveries (TWRP, OrangeFox, ..) allow the user unrestricted (root) access to the device.
Android ROM (rom) is the actual system (OS) and normally you would include the version that you are running.
Stock roms - Google 12L, AOSP xx, OOS 12, MIUI xx, ColorOS xx, ...
Custom roms - Lineage 19.1, crDroid 12.1, AospExtended 12.1, ...
In computer terms it would be..
Windows 7, Linux (Fedora 34), MacOS Monterey.​I am not sure what the current versions of MIUI and ColorOS are, hence the xx.​
Once the bootloader boots the device, a few things can happen.
- The system boot image (system kernel) takes over and boots the device into system (rom).
- The recovery boot image (recovery kernel) takes over and boots the device into recovery (mini Android environment).
- If system fails to boot, device reboots into recovery (Recovery Party) if recovery can boot.
- If no boot image takes over, you will stay in the bootloader, reboot into some special mode or just a good old fashion boot-loop.
There have been a lot of changes to Android though the years..
Each device, manufacture, Android version.. can be different from another.
The most common bootloader is (or supports) fastboot but, this is manufacture and device specific.
Not to be confused with fastboot_d (new story that started with Android 10/11?).​This has also changed though the years, some manufacture use their own variation of bootloader.
HTC had H-BOOT, Samsung does their own thing along with some other manufactures.
Rooting....
By default the substitute (switch) user su command is removed from Android.
This is what most refer to as superuser since it defaults to root user if you do not specify a substitute user.​
This has been a long and changing story in the Android world also.
Old but, well worth the read.
How-To SU - [chainfire.eu] - Link
The current most popular used root solution is Magisk.
It is a little more than just su. ​Magisk - [GitHub] - Link
---
It might be easier if you see an actual partition table.
Nexus 7 16 Gig WiFi - [PastBin] - Link
Might as well make it an ... interesting one.
In this example, userdata only has 1.2 Gigs since the rest is used by other partitions.
userdata is mounted as /sdcard.​
Save for boot, cache, system, misc, recovery and userdata.
The other partitions would be considered firmware.
When the device boots, the partitions get mounted to /dev/block.
Hope it helps more than confuse.
Cheers.

I have obtained the stock firmware for my device, how hard would it be to build generic android?

Hi, I just registered today to ask this question. Through somewhat simple means using the tools I had available, I was able to readback the stock rom from a TCL 20 XE 5087Z branded under Boost Mobile. I have successfully rooted via magisk and have confirmed that it is indeed the correct stock firmware through a bit of an accident, I forgot to patch vbmeta when flashing magisk_patched_boot.img, so in a panic, I flashed back all the roms I had read back from the device except userdata, and miraculously the device worked! Now the problem I run into is all the bloatware the carrier has installed on the phone. My main reason for rooting my device was I wanted the ability to prevent apps from being killed by the "Smart" manager on the device, because it seems that important apps keep getting killed by the built-in software. I ended up determining that the ram manager on the phone was killing apps based on the amount of ram available. Now that the phone is rooted, you would think I would have no problem getting rid of all the bloatware, except that whenever I forcefully uninstall the ram manager (com.tct.onetouchbooster), the app is still available on my apps menu and clicking on it with pretty much no delay opens the app right up as if the data had just been cleared. Now I have no idea what is causing this, probably another app, but I was wondering if maybe an easier alternative would be to get a generic android image for the device without bloatware that I can install just what I need. Now I say easier, but I find little documentation on how to do this, better yet if it will work. I have limited knowledge of how the android system works, mainly I just understand that /boot contains the bootloader, /system contains the os, and /userdata contains all the extra data apart from the stock image. If someone would enlighten me, would it actually be easier to build a generic image? Are there tools to do this? I understand that firmware is very touchy and that there is no "Generic" image in the sense, but having my stock rom available, would I be able to somehow generate a generic image based on the rom contents? If this would be way harder, how would I go about removing bloatware? I would not want to have to reset my phone each time I uninstall the wrong application, is there a non-data-damaging way to go about removing bloatware? If it ends up not being bloatware that is causing it and some hidden property somewhere in the stock rom config, how hard would it be to find that? Any help would be appreciated, and I am open to any comments and criticism. Please let me know how I might go about this, thanks in advance!
The stock firmware for this device can be found here: https://drive.google.com/file/d/1Q5IDP8V7PvuH2_1z63IFe23O2DF0cXZR/view?usp=sharing
The phone was bought from Walmart with prepaid Boost Mobile and it is a TCL 20 XE 5087Z with a MT6765 processor.
The password for the file is: xda5087Z-MT6765

Is the phone Project Treble enabled? If not don't waste your time.
A GSI is related to Project Treble, which means that the image can be installed on any Project Treble-supported device, regardless of the manufacturer, because it does not contain any hardware-specific components. The advantage is that a GSI can theoretically be used on any Project Treble-supported device.

xXx yYy said:
Is the phone Project Treble enabled? If not don't waste your time.
A GSI is related to Project Treble, which means that the image can be installed on any Project Treble-supported device, regardless of the manufacturer, because it does not contain any hardware-specific components. The advantage is that a GSI can theoretically be used on any Project Treble-supported device.
Click to expand...
Click to collapse
I downloaded the treble info app from the play store and indeed it is available with treble, the system image i need is system-arm64-ab.img.xz, would you mind pointing me in the right direction for how to install this? I'm assuming this just gets installed in the /system partition but let me know if I'm wrong. Thanks!

Can't help you, never did this.
You may look inside here:
[GUIDE] How to build a Project Treble GSI ROM from source? [31/08]
Hello guys, in this guide I'll try to simplify building Treble GSI process. As you read this guide now I'll assume you already have a previous knowledge about How to build android from source, so I won't cover some points with too many basic...
forum.xda-developers.com

Yes, only flash system.img. I recommend Android 10 (Android 11+ introduced restricted permissions)
[DISCONTINUED][GSI][10] LineageOS 17.x GSI (all archs)
Background: This is a natural continuation/extension of the LineageOS 16.0 GSIs I've been making since March 2019. If you clicked in here, I bet you know what LineageOS is already, but just to fill the blank: LineageOS is a free, community built...
forum.xda-developers.com

alecxs said:
Yes, only flash system.img. I recommend Android 10 (Android 11+ introduced restricted permissions)
[DISCONTINUED][GSI][10] LineageOS 17.x GSI (all archs)
Background: This is a natural continuation/extension of the LineageOS 16.0 GSIs I've been making since March 2019. If you clicked in here, I bet you know what LineageOS is already, but just to fill the blank: LineageOS is a free, community built...
forum.xda-developers.com
Click to expand...
Click to collapse
DO NOT DO THIS!!!! The TCL 20 XE is NOT compatible with Android 10 (it only supports something 30, which corresponds to Android 11), and the device will bootloop. I have made this mistake but I can not reach fastboot as the option is not in the recovery, therefore I need to run "adb reboot fastboot" within Android. MTKClient should fix this if you can find a stock super.img file for the 5087z.

note "adb reboot fastboot" is for fastbootd which is in recovery, while "adb reboot bootloader" is for fastboot (you can always enter from Volume button, regardless of destroyed boot/system partition)
boot-loop is probably caused by dm-verity, you forgot vbmeta?

alecxs said:
note "adb reboot fastboot" is for fastbootd which is in recovery, while "adb reboot bootloader" is for fastboot (you can always enter from Volume button, regardless of destroyed boot/system partition)
boot-loop is probably caused by dm-verity, you forgot vbmeta?
Click to expand...
Click to collapse
Fastbootd doesn't have an option in the recovery on my model, I've seen other TCL 20 XE phones have it though (I have the Boost Mobile varient like the thread maker), however Fastbootd let's me boot into recovery. I was only able to flash the stock ROM with MTKClient, which mikedcoombs thankfully provided (I just needed the super partition). For vbmeta, I just have an empty vbmeta that I flashed when I first rooted the phone. I don't think it is dm-verity, because LineageOS 20 as an GSI worked except for the Wi-Fi.