[Guide] How to create EXT4 images. - Android General

Since most of the high-end devices are using now EXT4 partitions i decided to make a guide.
I am doing this because this is the easiest way to create an EXT4 image.
This is not my guide I am just adapting and make it clear to everybody; someone showed me how to do this (I will mention him at the end of the guide).
Let's assume that you dumped the system.img from your own device and you want to add something to it.
We will create a new system.img and we will name it system_new.img, the size will be 240 Mb.
Step 1
Linux Machine (I used Ubuntu)
We prepare the directories and copy the system.img in the folder in which we will work.
mkdir system (here we will mount the old system.img
mkdir system_new (here we will mount the system_new.img)
Step 2 – Creation of the actual EXT4.img
dd if=/dev/zero of=system_new.img bs=4k count=60000
Translation of the terms,
bs =blocksize, 4k= the size of the block`s which in this case is 4kb
count=60000, the number of block`s, in our case will result an image of 240 Mb.
The blocksize can be 1k/2k/4k/16k
To get the exact size of the image that you create use simple maths.
60000 * 4 = 240000
Step 3 Formating the system_new.img with EXT4
mkfs.ext4 system_new.img
It will be a question where you will select yes (Y)
We override the file system check (If you don`t do this, the image will not work)
tune2fs -c0 -i0 system_new.img
Step 4 We mount the directories that we previous created.
mount -o loop system_new.img system_new/
mount -o loop system_new.img system/
Step 5 We copy the content from the old system.img in the system_new.img
cp -v -r -p system/* system_new/
We sync the files
sync
Step 6 Unmounting the partitons.
umount system_new/
umount system/
Step 7 Enjoy your new ext4 system.img
Tips:
If you are using Ubuntu just type
sudo su
And you will be root and no more sudo at each command.
You can add new files in the new created system.img but you need to set the permissions and ownership properly, otherwise it will not work.
Credits: arctablet.com administrator.

work perfect!
I managed to create a new system img for huawei phone.

Errors in Step 3 and 4: Unable to proceed
Hi There,
I am getting errors in step 3 and 4.
Step 3 Formating the system_new.img with EXT4
mkfs.ext4 system_new.img
It will be a question where you will select yes (Y) -- after this below error comes
Device size reported to be zero. Invalid partition specified, or partition table wasn't reread after running fdisk, due to a modified partition being busy and in use. You may need to reboot to re-read your partition table.
We override the file system check (If you don`t do this, the image will not work)
tune2fs -c0 -i0 system_new.img -- after this below error comes
Attempt to read block from filesystm resulted in short read while trying to open system.img
Step 4 We mount the directories that we previous created.
mount -o loop system_new.img system_new/ -- after this below error comes
unknown filesystem type 'ext4'
Could you please help.

i whant to create and system.img.ext4 for my android ! ! But i saw that image which is created is just system.img ! I`m using ubuntu and i whant to know what is need it to create that system.img.ext4 ! I don`t see that img to be ext4 file ! Thanks

jabarel said:
i whant to create and system.img.ext4 for my android ! ! But i saw that image which is created is just system.img ! I`m using ubuntu and i whant to know what is need it to create that system.img.ext4 ! I don`t see that img to be ext4 file ! Thanks
Click to expand...
Click to collapse
I'm not sure but it's probably just a matter of file extenstion.
By the way, great tuto. May be someting to add :
Android ext4 don't seem to be the exact standart of linux ext4 file systems.
To make it fully compatible and usable with fastboot, the use of "ext2simg" can be useful.
So it will be something like this :
ext2simg fs2convert.img fsconverted.img
ext2simg can be found in android-tools in debian repository.

I am porting a rom ,i extracted "system.new.dat" into "sytem" folder , applied changes according to this guide to port a ROM -->> http://forum.xda-developers.com/showthread.php?p=65933478#post65933478
can you tell me how to reconstruct the "system.new.dat" from "sytem" folder ?

is mkfs.ext4 applet available to arm devices..??

you can do it faster...
Great if you create a new image, but to edit no need to create all these steps ...
Just copy the system.img to system_new.img and mount that one and edit..

There's no clear instruction!
Hours of researching many places and no good instruction about how to create or edit an EXT4 with or without Linux!
I know this is an old post but I just wanted to try, might get a reply!

Frank2406 said:
Hours of researching many places and no good instruction about how to create or edit an EXT4 with or without Linux!
I know this is an old post but I just wanted to try, might get a reply!
Click to expand...
Click to collapse
what is not clear?
this has been tested by me and it works.
there are more refined ways in doing it, it just depends on what you need to to with the ext4 image.

globula_neagra said:
what is not clear?
this has been tested by me and it works.
there are more refined ways in doing it, it just depends on what you need to to with the ext4 image.
Click to expand...
Click to collapse
Step 1: "We prepare the directories" you said. What directories?
"mkdir system"
"mkdir system_new" which, what or where are they?
Step 2: The whole step 2 for a newbie in Linux like me is bla bla bla except the title "Creation of the actual EXT4.img"!
And the rest of your guide is as the same as step 2 which I mentioned.
And if this guide is for Ubuntu experts then maybe in the beginning you could mention so people don't get their hopes up dear globula_neagra!!
Long story short, I just wanted to try a custom Rom on my Zenwatch 1, but I've forgot to make backup, so the official Rom was gone. Asus itself didn't help to get a copy of the official one, so I tried Anthias custom Rom instead, but that made the watch even worse.
Then I started to research how to fix it, so I found this article.

It s not a step by step guide on how to use ubuntu.
I assume that wheen you want to learn something you do use google too. For this instance i would google in this way "what does mkdir command in ubuntu"
After i understood the purpose of the command and how to use it i would try to apply it using the guide and after that you will see that things will start to make sense.
My guide was written with the idea that if you use android you have an idea of linux too and in this case ubuntu.
The command line in linux is somewhat similar to the one in windows commander there are some extra things that you need to learn but those can t be put in a guide like this.
In regards to your watch. My advice is to find another one and take a system dump from that one and flash it to yours if you have an unlocked bootloader.

Here you cand find some good reads on how to dump the files from the watch. And a bit more details on what is the business with the ext4 creation. Topic is5 years old but still relevant.
http://www.arctablet.com/blog/forum/arnova-7c-g3/arnova-7c-g3-dev-topic/

Related

android's init / working with .img files

hey everyone, this all started when i began to try and get my sd partitioned for apps. i have the stock rogers fw with haykuro's root based off cyangens recovery? anyway, i got the partition to work and all and even copied files over. my only problem is that the ext2 does not mount unless i do it manually from the terminal on device. i have come up with an init.rc file that i believe should work. currently it is in /etc
Code:
on boot
export PATH /data/busybox
mount -rw -t ext2 /dev/block/mntblk0p2 /system/sd
on device-added-/dev/block/mntblk0p2
mount -rw -t ext2 /dev/block/mntblk0p2 /system/sd
any ideas?
Tried lucids script to do everything?
http://forum.xda-developers.com/showthread.php?t=480582 I mean I know that rom you have has a adds2sd thing in it, but I can only speak with what I use and know. =)
i'll check it out, but my rom is stock. there is no apps2sd in it. i just partitioned and was going to set up some links when i realized the partition wasn't mounting on it's own. thanks for the link though
The init.rc isn't a shell script, and doesn't run normal commands - its built-in mount command has a different syntax from normal mount. Check out the source or other init.rc files for the syntax.
gwydionwaters said:
i'll check it out, but my rom is stock. there is no apps2sd in it. i just partitioned and was going to set up some links when i realized the partition wasn't mounting on it's own. thanks for the link though
Click to expand...
Click to collapse
Check your PM
i figured it out a little, i have noticed that the init i create is being overwritten when i reboot. i would assume perhaps i need to add the modified file into the system.img and then flash that version on? does that sound right to anyone?
The init is flashed during boot. Its in the boot.img. you can check the stickys to see how to crack one open and put it back together. Ill fix it for you this weekend as promised. Ill even show you what I did but I gotta get time at my computer. Patience my internet friend, patience.
Edit
Also check the "all you need to know" post by haykuro. Its the most recent thread started by him in this forum I believe
If you are using a stock rom did you get the modified mount.conf that supports partition mounts?
lol no i didn't know there was one. i did modify my mount.conf on my own and added the entry for the ext.
i'm having some serious trouble unpacking my boot image, and yes i have read all there is to read and then some. i originally tried unyaffs on the image i got from my nandroid back up i made before root, but it was claiming a broken image. so i made a current back up and tried that boot, the same problem. i figured maybe the nandroid backup utility was creating bad images so i went another route. i started on device and created an image of my boot mount
Code:
cat /dev/mtd/mtd2 > /sdcard/boot.img
i stripped off the header and kernel, saved the remainder as a raw file. then
Code:
gunzip -c boot | cpio -i
and it sort of works, maybe with errors and then asks for the name of archive 2 ..
cpio: Cannot identify format. Searching...
cpio: Cpio file name length 46200 is out of range
cpio: Invalid header, starting valid header search.
cpio: Cpio file name length 6960 is out of range
cpio: Cpio file name length 40367 is out of range
cpio: Cpio file name length 21330 is out of range
gunzip: /device/here/boot: decompression OK, trailing garbage ignored
cpio: End of archive volume 1 reached
ATTENTION! cpio archive volume change required.
Ready for archive volume: 2
Input archive name or "." to quit cpio.
Archive name >
Click to expand...
Click to collapse
and if i enter anything it can't find/read the file (the one i named of course) and if i quit there is nothing gained, no files or anything

[HOW-TO] ROM-HACKING: init.rc ext2-auto-mount / ROM Signing / ROM Kitchen

AS MENTIONED IN THE INTRODUCTION TEXT THIS HAS ONLY BEEN TESTED ON AMON RA ROM 1.6.2 BUT SHOULD REALLY WORK ON ANY ROM THAT HAS NO EXT2 AUTO-MOUNT. AND YEAH THIS WHOLE PROCESS HAS BEEN DONE ON A 32a BOARD. FOR THOSE THAT TRY THIS ON OTHER ROMS LET ME KNOW HOW IT GOES.
I've searched and shuffled through the entire forum and made inquiries to ROM authors without much light being shed on this issue. I doubt I am the only one who has been looking for a way of doing this so I decided to do a small HOW-TO. Here I will explain step by step as to how you can implement a script to be part of your ROM that will auto mount an ext2 partition on boot up if such partition is present. I have included all the tools I've used in order to pull this off, and as the title suggests this has only been done on Amon Ra's latest 1.6.2 ROM. In order to follow these instructions you are expected to allready have set up an adb enviroment on your linux box and for the signing process to work you must have sun-java present, the gnu java wont work. And of course a microSD card with an ext2 partition
1. Download install.sh to your home directory
Code:
wget http://www.grindhouse.no/androidtools/install.sh
chmod a+x install.sh
2. Now execute the install.sh script which will create a directory to work in and download a tool and script package and unpack it.
Code:
./install.sh
When the install.sh script is done you need to move the mkbootimg preferebly to your tools directory of your SDK.
Code:
mv toolstomove/mkbootimg <path/to/sdk/tools/mkbootimg>
3. Unpack the RA1.6.2 ROM into a directory in your home dir. In this HOW-TO we will use directory name "ra1.6.2" as an example through out the entire process.
4. Copy the boot.img from ra1.6.2 to the ROM-cooker dir
Code:
cp $HOME/ra1.6.2/boot.img $HOME/ROM-cooker/boot.img
cd $HOME/ROM-cooker
5. Use unpack.pl to extract the ramdisk from the boot image. I've modified the script a little so it automates the entire process and decompresses the ramdisk to a directory
Code:
./unpack boot.img
6. Now you can either replace the init.rc file here with the one I've included in this package or you can add these lines by yourself. In wich case do the following
Code:
cd boot.img-ramdisk
pico init.rc
Press CTRL+w and then CTRL+t and input 27. hit enter. This will take you to line 27 of init.rc so you can add a line right before the init process remounts the rootfs in read-only mode. Add following line:
Code:
mkdir /sdext2 0771 system system
Now scroll down to the end of the init.rc file and add the following:
Code:
service mountsdext2 /system/bin/mountsd
user root
group root
oneshot
7. You have now edited (or replaced) your init.rc file and prepared it to execute a script on boot that will detect an ext2 partition and boot it if there is one to be found. Now you have to make the mountsd script a part of the ROM. Do the following:
Code:
cd $HOME/ROM-cooker
mv toolstomove/mountsd $HOME/ra1.6.2/system/bin/mountsd
rm -rf toolstomove
8. Now that the init.rc file is sorted out and mountsd has been placed in /system/bin of the ROM so it is time to re-pack the boot.img:
Code:
cd $HOME/ROM-cooker
./repack boot.img-kernel boot.img-ramdisk boot.img
rm $HOME/ra1.6.2/boot.img
mv boot.img $HOME/ra1.6.2/boot.img
9. Your ROM now has a new boot image with an updated init.rc and the /system/bin dir has the script needed to auto-mount the microsd ext2. Now you must re-zip the ROM and sign it. Do the following:
Code:
cd $HOME/ra1.6.2
zip -r update.zip *
mv update.zip $HOME/ROM-cooker/update.zip
cd $HOME/ROM-cooker
./sign.pl update.zip
10. The ROM is now signed and you now have a file called update-signed.zip. Connect the phone to your computer and execute thus:
Code:
./push update-signed.zip
11. Now you are ready to flash the modified ROM which will auto-mount an ext2 partition on your microSD. There is no need to wipe before flashing. If you have no prior experience with ROM flashing or whatever just backup your current install. If you're using OpenHOME or anything similar, nothing will be changed or damaged but if you're using MontAlbert's themes with the ROM you will have to flash them again after flashing this modified ROM.
Code:
adb reboot recovery
12. Flash from choose zip and of course choose update-signed.zip. Reboot. After the system boots up again you can now check whats what with either one of the commands:
Code:
[email protected]:~$ adb shell mount | grep sdext2
/dev/block/mmcblk0p2 on /sdext2 type ext2 (rw,noatime,nodiratime,errors=continue)
[email protected]:~/boot$ adb shell busybox df -h | grep sdext2
/dev/block/mmcblk0p2 893.7M 13.0K 846.0M 0% /sdext2
13. Voila! Your RA 1.6.2 ROM now detects and mounts your microSD ext2 partition on boot. Woohoo?
I hope the HOW-TO was easy reading and that you have succeeded in hacking up your ROM. I know that certain ROMs have this as a built-in function but Amon Ra's does not. But since alot of people including myself use his ROM because of the high speed and stability I thought I should contribute to his project and add a cool (and missed?) function to it.
Mind you that you can use the ROM-cooker set to further adjust and hack up the ROM as you see fit. Happy learning!
Very nice!
Now the question many people will ask : why would you automount ext2 if you don't use apps2sd ?
I personally have ubuntu on my ext2 And besides this approach can be used for a number of things, people who have had the need, or wanted to experiment with init.rc doing things on boot, the mountsd script can easily be altered to do what ever needed.
For me its been a learning curve finding these things out, so by sharing it I may spare some people breaking their backs over this whole init.rc thing. people may want to modify init.rc for whatever reason, so I'm sure people wont have a problem finding a way of putting this to use, and its a subject that isnt all that covered on the forum .. and hey .. at least they get a rom kitchen out of the whole shabang
Very interesting! Thank you.
I used your unpack-program to unpack a recovery-image. It seems to work fine. What I am trying to do is change the state the recovery-image returns the phone to. Would it be possible to just replace your mountsd-script with, for example, a script that installs apps? Or is there a better way to do what Im trying to achieve?
Cheers,
edit: I noticed that on the emulator it is sufficient to just place an apk-file in "data/app" to get it installed. Could it be possible that this is all I need a script to do? :O or could I hurt my poor phone by doing so you think?
sandis84 said:
edit: I noticed that on the emulator it is sufficient to just place an apk-file in "data/app" to get it installed. Could it be possible that this is all I need a script to do? :O or could I hurt my poor phone by doing so you think?
Click to expand...
Click to collapse
That's indeed all you need to do.
Hi!
So I tried to create a signed update.zip, but it failed. It didnt create a "update-script"-file, so my device refused to install it. I wrote my own "update-script"-file, but then it complained "no digest" for the file. How do I solve this?
post the contents of your script people might see whats up
so is this all on linux?
also where are the script files for your tutorial
thanks for the time to put together
sitimber said:
so is this all on linux?
also where are the script files for your tutorial
thanks for the time to put together
Click to expand...
Click to collapse
Says where its at in the first line : )
Code:
wget http://www.grindhouse.no/androidtools/install.sh
But now that I checked, I have to apologize, I see I have a missed payment with my hosting, I'll fix that within the day. Also sorry I havent been answering the few questions here I've been afk cause of surgery.
sitimber said:
post the contents of your script people might see whats up
Click to expand...
Click to collapse
well, I looked in another "update-script" file and found this:
assert compatible_with("0.2") == "true"
assert getprop("ro.product.device") == "dream" || getprop("ro.build.product") == "dream"
show_progress 0.5 0
write_radio_image PACKAGE:radio.img
show_progress 0.5 10
Click to expand...
Click to collapse
So I figured that nothing was essential other then the line "write_radio_image PACKAGE:radio.img". Also ofcourse I made sure it contained the name of my image-file instead of "radio.img". This gave me the "no digest" message, so now I feel unsure on how to create a working update.zip.
edit:
SOLVED! How silly of me. When you sign the update, a hash of each file is put in manifest.mf. Since I added the update-script after signing the file, ofcourse the digest(hash) was missing. Now everything works alot better and I can proceed... until I get stuck again
Cheers,
edit2:
Just to get a better understanding, what exactly does each line do here? Or where can I read about this?
Code:
service mountsdext2 /system/bin/mountsd
user root
group root
oneshot
edit3:
Ok, so I have experimentet, but I still dont manage to solve those last steps. I tried to edit init.rc and just add "mkdir /testdir 0000 system system" where the other directories were created. I then repacked it, zipped it, signed it, put it on my sdcard, started up a custom recovery, installed the update and rebooted. Everything seems to work fine. But when I start adb and check around, I dont see the "testdir"-directory. Also when I check in init.rc my line is gone. Do you guys have an idea of where I went wrong?
sitimber said:
so is this all on linux?
also where are the script files for your tutorial
thanks for the time to put together
Click to expand...
Click to collapse
it doesnot necesarily have to be linux ...you can also do it in windows using cygwin and dsxda's android rom kitchen

[Noob Friendly][Guide] How to extract .ext4 file while using linux !

There may be alot of guides out there how to make flashable zip of your ftf released by Sony ! But extracting ext4 files can be a headache !
I tried searching alot ! learned alot ! there were so many information that a Noob(like me) can be so much confused !
You can extract .ext4 file on windows also but that may cause BOOTLOOP also ! [PERSONAL EXPERIENCE]
So here are the simple steps to extract .ext4 files easily in linux !
1) open terminal
2) type
sudo nautilus
Click to expand...
Click to collapse
this will open dialogue box with admin privilage
3) place ext4 file on the desktop and create a folder named mounted in the same directory
4)than type following in terminal,
sudo mount -o loop /root/desktop/system.ext4 /home/USERNAME/Desktop/mounted
Click to expand...
Click to collapse
(Basic Structure of that command is: sudo mount flag loop ext4 directory mounted directory !)
HERE;
/root/desktop/system.ext4 is the directory of .ext4 file
/home/USERNAME/Desktop/mounted is the directory of destination folder !
AND DONE ! You can grab those files and put in system folder of your zip file !
NOTE THAT: THIS EXTRACTED DATA WILL BE ODEXED !
ShivangDave said:
...
Click to expand...
Click to collapse
Hi, This was the guide which i was really looking for but unfortunately the code is not working for me in can you please check it again ?
Edit: Thanks it worked ! Great. The explanation for the code given by you helped me solving it ! Thanks a lot bro
M4ST3R-V said:
Hi, This was the guide which i was really looking for but unfortunately the code is not working for me in can you please check it again ?
Edit: Thanks it worked ! Great. The explanation for the code given by you helped me solving it ! Thanks a lot bro
Click to expand...
Click to collapse
Glad to hear that
ShivangDave said:
Glad to hear that
Click to expand...
Click to collapse
desktop is spelled with a capital D
thank you! using today this noob guide, very helpfull!!!
Buddy..I wanna try making a zip from ftf.
So I have extracted the system.sin into a folder system...
Now I need meta-inf to be kept along with system into a zip right....
So if I go wrong somewhere will I brick my phone..
Also can I simply delete all the unwanted apps from apps folder?
Please..I know you are a guy who knows all these stuff..I saw many guides,yet I am afraid if somethin bad will happen to my device..
Plz help me... I need you badly.
Hit the thanks button..it does not cost you anything.
it's worth something for me...
sent from my Sony Xperia e dual
mathewsj114 said:
Buddy..I wanna try making a zip from ftf.
So I have extracted the system.sin into a folder system...
Now I need meta-inf to be kept along with system into a zip right....
So if I go wrong somewhere will I brick my phone..
Also can I simply delete all the unwanted apps from apps folder?
Please..I know you are a guy who knows all these stuff..I saw many guides,yet I am afraid if somethin bad will happen to my device..
Plz help me... I need you badly.
Hit the thanks button..it does not cost you anything.
it's worth something for me...
sent from my Sony Xperia e dual
Click to expand...
Click to collapse
http://forum.xda-developers.com/showthread.php?t=2183077
ShivangDave said:
There may be alot of guides out there how to make flashable zip of your ftf released by Sony ! But extracting ext4 files can be a headache !
I tried searching alot ! learned alot ! there were so many information that a Noob(like me) can be so much confused !
You can extract .ext4 file on windows also but that may cause BOOTLOOP also ! [PERSONAL EXPERIENCE]
So here are the simple steps to extract .ext4 files easily in linux !
1) open terminal
2) type
this will open dialogue box with admin privilage
3) place ext4 file on the desktop and create a folder named mounted in the same directory
4)than type following in terminal,
(Basic Structure of that command is: sudo mount flag loop ext4 directory mounted directory !)
HERE;
/root/desktop/system.ext4 is the directory of .ext4 file
/home/USERNAME/Desktop/mounted is the directory of destination folder !
AND DONE ! You can grab those files and put in system folder of your zip file !
NOTE THAT: THIS EXTRACTED DATA WILL BE ODEXED !
Click to expand...
Click to collapse
nautilus is just for ubuntu, mention that you need to swap nautilus with your file manager if you're using a different distro other than ubuntu(e.g lubuntu= pcmanfm )
Also when using GUI and sudo, it's best to use gksudo instead of sudo.
Hi,
It works fine, so thanks for that, but I end up with a ''volume of 682 MB''. Unmounting and ejecting doesn't work and simply deleting it, also won't work. Does anyone have any idea how to remove this ''device'' from my system? It's quite annoying and takes in space.
Thanks!
Never mind , a reboot fixed it...
Sent from my C1505 using XDA Premium 4 mobile app
ShivangDave said:
1) open terminal
2) type
Code:
sudo nautilus
this will open dialogue box with admin privilage
3) place ext4 file on the desktop and create a folder named mounted in the same directory
4)than type following in terminal,
Code:
sudo mount -o loop /root/desktop/system.ext4 /home/USERNAME/Desktop/mounted
Click to expand...
Click to collapse
First off let me say that I am in no way a Linux user, but I tend to be quite resourceful when it comes to researching. This one is beginning to stump me. Second, I am using crunchbang {a Debian (Wheezy)} build and therefore I had to modify the coding a little bit.
This is what I did just to even get it to accept my query without issues
Code:
sudo nautilus
This pulled up my Desktop in File Manager with root privileges. I created the mounted folder and put the system.img.ext4 in the Desktop location. Debian, or crunchbang, does not have a physical Desktop for placing files, as far as I have learned, just this folder located in the root folder. Anyways, after doing those two things I did this
Code:
sudo mount -t ext4 /root/Desktop/system.img.ext4 /root/Desktop/mounted
This was the first code I tried that didn't return any error about the location, fs, or anything. Feeling hopeful that I had finally figured out and was going to be able to access my system.img I look at my Desktop folder and open up the mounted folder, what do I see? Lost+Found folder with nothing in it, and a hidden folder called .Trash-0 which contains two folders "files" and "info". "files" contains a folder just like the non-hidden lost+found with nothing in it and the "info" folder which contains an 0byte file titled lost+foundinfo. My system file is over 2GB in size, so I am at a standstill because I do not know how to proceed.
jacodaburr said:
First off let me say that I am in no way a Linux user, but I tend to be quite resourceful when it comes to researching. This one is beginning to stump me. Second, I am using crunchbang {a Debian (Wheezy)} build and therefore I had to modify the coding a little bit.
This is what I did just to even get it to accept my query without issues
Code:
sudo nautilus
This pulled up my Desktop in File Manager with root privileges. I created the mounted folder and put the system.img.ext4 in the Desktop location. Debian, or crunchbang, does not have a physical Desktop for placing files, as far as I have learned, just this folder located in the root folder. Anyways, after doing those two things I did this
Code:
sudo mount -t ext4 /root/Desktop/system.img.ext4 /root/Desktop/mounted
This was the first code I tried that didn't return any error about the location, fs, or anything. Feeling hopeful that I had finally figured out and was going to be able to access my system.img I look at my Desktop folder and open up the mounted folder, what do I see? Lost+Found folder with nothing in it, and a hidden folder called .Trash-0 which contains two folders "files" and "info". "files" contains a folder just like the non-hidden lost+found with nothing in it and the "info" folder which contains an 0byte file titled lost+foundinfo. My system file is over 2GB in size, so I am at a standstill because I do not know how to proceed.
Click to expand...
Click to collapse
change the directory if possible, and change the command according to it.. Because I'm in no way a crunchbang user let me know if i can help in any other way though...
sudo mount flag loop ext4directory mounteddirectory
ShivangDave said:
change the directory if possible, and change the command according to it.. Because I'm in no way a crunchbang user let me know if i can help in any other way though...
sudo mount flag loop ext4directory mounteddirectory
Click to expand...
Click to collapse
trying to use that code with flag and/or loop returns this
Code:
Usage: mount -V : print version
mount -h : print this help
mount : list mounted filesystems
mount -l : idem, including volume labels
So far the informational part. Next the mounting.
The command is `mount [-t fstype] something somewhere'.
Details found in /etc/fstab may be omitted.
mount -a [-t|-O] ... : mount all stuff from /etc/fstab
mount device : mount device at the known place
mount directory : mount known device here
mount -t type dev dir : ordinary mount command
Note that one does not really mount a device, one mounts
a filesystem (of the given type) found on the device.
One can also mount an already visible directory tree elsewhere:
mount --bind olddir newdir
or move a subtree:
mount --move olddir newdir
One can change the type of mount containing the directory dir:
mount --make-shared dir
mount --make-slave dir
mount --make-private dir
mount --make-unbindable dir
One can change the type of all the mounts in a mount subtree
containing the directory dir:
mount --make-rshared dir
mount --make-rslave dir
mount --make-rprivate dir
mount --make-runbindable dir
A device can be given by name, say /dev/hda1 or /dev/cdrom,
or by label, using -L label or by uuid, using -U uuid .
Other options: [-nfFrsvw] [-o options] [-p passwdfd].
For many more details, say man 8 mount .

Extract files from stock firmware images

Hi,
when I still hadn't the device, I wanted to know exactly what's included in stock ROMs to have a better idea of what to expect. I hence downloaded a stock firmare and the stock system.img (see below for the steps).
Ok, so what? Well, when KK was released I decided to do the same (I was still waiting for the device), but I couldn't. Unlike before, I didn't find a single system.img, but multiple files (3 to be exact, maybe it's too big to be flashed at once with fastboot, I don't know, I'm new to this) and couldn't understand how the original image was splitted to generate those files.
Did anyone see something similar already and sucesfully merged splitted filesystems?
I know I could simply ask for a system dump (or wait for KK), but now I'm curious to know on how to do this. I tried few things but I couldn't find any way to do it. Maybe I could see how fastboot treat these files, but I wonder if anyone already knows the answer.
Anyway, here the steps to mount the system.img of our stock JB firmwares. Maybe there's an easier way, I honestly don't know. As far as I know, converting the sparge image should be enough, but I had to do more:
Code:
#Convert sparse image with simg2img
simg2img system.img system.img.raw.tmp
#UTF8 may slow down grep, switch to C
export LANG=C
#Look for the ext4 magic and calculate its position
magic=`grep -aobP -m1 '\x53\xEF' system.img.raw.tmp | head -1 | cut -d":" -f1`
offset=$(($magic-1080))
#Remove extra header with dd
dd if=system.img.raw.tmp of=system.img.raw ibs=$offset skip=1
#Remove temp file
rm system.img.raw.tmp
Now you can mount system.img.raw as a normal ext4 filesystem.
Just concatenate the three chunks together like so:
Code:
cat system.img_sparsechunk1 system.img_sparsechunk2 system.img_sparsechunk3 > system.img
Then apply the steps from the OP and voilà!
Edit: Scratch that: the image is accessible, some files are visible but others are missing. To be continued...
Darkshado said:
Just concatenate the three chunks together like so:
Code:
cat system.img_sparsechunk1 system.img_sparsechunk2 system.img_sparsechunk3 > system.img
Then apply the steps from the OP and voilà!
Edit: Scratch that: the image is accessible, some files are visible but others are missing. To be continued...
Click to expand...
Click to collapse
As you have found that doesn't work, remember that each file will have metadata headers so that may be one reason you can't just cat them together.
To OP - can't you just mount each img as a filesystem and copy all the files from each mounted filesystem to another entirely separate directory. At least that way you have all the files in one place, eg copy
/sparsechunk1/system/file1 to /newdir/system/file1
And so on.
scott_doyland said:
As you have found that doesn't work, remember that each file will have metadata headers so that may be one reason you can't just cat them together.
To OP - can't you just mount each img as a filesystem and copy all the files from each mounted filesystem to another entirely separate directory. At least that way you have all the files in one place, eg copy
/sparsechunk1/system/file1 to /newdir/system/file1
And so on.
Click to expand...
Click to collapse
Only the first chunk can be mounted, the other two are not recognized as filesystem and there's no way to mount them.
It's not as if /system was divided in three parts and then an image for each one was created, so that you can treat them as separate files (what you said would work in this case).
One image is created and then it's splitted in three in some unknown way. The first image is the one that holds the informations to access the files, the other two just pieces of files that can't be accessed without the informations in the first chunk.
mfastboot knows how to correctly copy the data from the separate images with the right offsets inside the phone so that in the end all the files can be accessed. Concatenating the files using dd using the correct offsets could maybe work, but after a few attempts I gave up.
There is method to extract files under Windows
Al936 said:
There is method to extract files under Windows
Click to expand...
Click to collapse
Any change you happen to be willing to share the contents of or principles behind `sparse2img.exe`?
HolySid said:
Any change you happen to be willing to share the contents of or principles behind `sparse2img.exe`?
Click to expand...
Click to collapse
What kind of principles you expect from me? I just posted the link to one of the method to extract all files and folders from stock firmware's system partition. The tools were not developed by me - I just informed XDA community about it. As you can see from the tread several persons already confirmed that it works.
Al936 said:
What kind of principles you expect from me? I just posted the link to one of the method to extract all files and folders from stock firmware's system partition. The tools were not developed by me - I just informed XDA community about it. As you can see from the tread several persons already confirmed that it works.
Click to expand...
Click to collapse
Oh, I'm sorry, I thought it was your work. I just want to know how to merge the system files. I know the exe is working, but I'm running Linux, so my question it is both out of curiosity and simply because I cannot run the code.
Try running it with wine or in virtual machine.
sent via tapatalk
Thanks, I managed it by using another laptop. But still, I'd rather know what happened
Sent from my XT1032 using xda app-developers app
Darkshado said:
Just concatenate the three chunks together like so:
Code:
cat system.img_sparsechunk1 system.img_sparsechunk2 system.img_sparsechunk3 > system.img
Then apply the steps from the OP and voilà!
Edit: Scratch that: the image is accessible, some files are visible but others are missing. To be continued...
Click to expand...
Click to collapse
I just replaced the first line in the OP's instructions with this to join the system.img_sparsechunk files:
Code:
simg2img system.img_sparsechunk.* system.img.raw.tmp
And then the rest worked fine. Here were the exact steps I took (I shortened it a tiny bit, but it's the same concept):
Code:
simg2img system.img_sparsechunk.* system.img.raw.tmp
offset=`LANG=C grep -aobP -m1 '\x53\xEF' system.img.raw.tmp | head -1 | awk '{print $1 - 1080}'`
dd if=system.img.raw.tmp of=system.img.raw ibs=$offset skip=1
sudo mkdir /mnt/system
sudo mount system.img.raw /mnt/system
SenorChang said:
I just replaced the first line in the OP's instructions with this to join the system.img_sparsechunk files:
Code:
simg2img system.img_sparsechunk.* system.img.raw.tmp
And then the rest worked fine. Here were the exact steps I took (I shortened it a tiny bit, but it's the same concept):
Code:
simg2img system.img_sparsechunk.* system.img.raw.tmp
offset=`LANG=C grep -aobP -m1 '\x53\xEF' system.img.raw.tmp | head -1 | awk '{print $1 - 1080}'`
dd if=system.img.raw.tmp of=system.img.raw ibs=$offset skip=1
sudo mkdir /mnt/system
sudo mount system.img.raw /mnt/system
Click to expand...
Click to collapse
It worked. Thank you!

[DUAL_BOOT]Dual booting an android phone with an extrrnal SD card

So here you come. To read and perform this tutorial, you obviously need a first hand experience on flashing a ROM and/or kernels. Otherwise this tutorial and my efforts to get you a device with two OSes running might end up giving you a bricked device. So, if you're hearing the terms "flashing" or 'kernels' for the first time and thinking it's kinda good food, then bro, just go and taste those first.
Something's to remind before we gonna dig deep into this tutorial->
1> Noone but you will be responsible for what you end up with.
2> The warranty of your device will be voided after this if it isn't already after rooting. For MI users, the good news is that you can reclaim it by just flashing the fastboot ROM for your device.
Enough lectures. Bro let's get to work.
This you'll be needing =>
1> One working Windows PC(because I doesn't know any replacement of bootimg.exe on any other OS. If you know, then let me).
2> A class 10 memory card ( I recommend 32GB for the spaces)
3> A custom ROM and kernel for your phone(the second os)
4> Any custom CWM based recovery installed.(since TWRP is most popular, I will demonstrate using it. You can use any other you want overall process will be the same)
5> ADB, fastboot and the device drivers (easily found in XDA)
PART 1: MODIFYING THE BOOT
At first, how does your device boots up? What are the partitions called /data and /system? The answer is quite simple. It's your kernel that points out the location from where the OS should be picked up. So for booting into the second OS we need some modifications to it at first.
Search and download bootimg.exe on XDA, I'll post a link later. Create two folders. Name them "Internal OS" and "External OS" respectively. Put the zip file of the OS you're currently using to the first one and the OS you're gonna use on the external storage to the second one. Rename the second OS to originalExternalOS.zip. Extract originalExternalOS.zip. Pick the boot.img file from the root of the extracted folder and move it to a new folder named "boot2". Extract the IMG using bootimg.exe. Navigate to the initrd folder and you will get a file named 'fstab".
Basically it's the file that tells the kernel which partition does the OS resides in.
Open the file in your favourite text editor.
Replace every instance of the first line with the second one:
/dev/block/bootdevice/by-name/system => /dev/block/mmcblk1p2
/dev/block/bootdevice/by-name/userdata => /dev/block/mmcblk1p3
/dev/block/bootdevice/by-name/cache => /dev/block/mmcblk1p4
Save the file without giving any extension to it. Repack it using the same tool. You'll have boot-new.img and boot-old.img. Rename boot-new.img to boot.img and replace the one in the root folder with this. Basically what we're doing here is replacing the old boot.img with the modified one.
For your knowledge, blocks are the partitions of any storage you have on your device. For example, your internal storage is partitioned to near about 30 different blocks each starting with prefix "mmcblk0p". We here just told the kernel to load the OS from the blocks mentioned. We'll be creating these blocks in the external SD card next.
PART 2: PARTITIONING THE SD CARD
Connect your device with the memory card inserted to your PC. If you haven't installed fastboot, ADB, and the drivers, do it now.
READ THE FOLLOWING CAREFULLY
Reboot the device to recovery mode. Type the commands in cmd:
Code:
adb shell
parted
unit MB
print
quit
umount external_sd
Read and store the minimum and maximum capacity of your card. Since different cards will have different capacities I will point it as variable MIN_SIZE and MAX_SIZE. You'll need to calculate and put the values in the commands. Now type the following commands on cmd:
Code:
parted /dev/block/mmcblk1
rm 1
//START_BLOCK = MAX_SIZE - 5000
mkpartfs primary fat32 MIN_SIZE START_BLOCK
//SYS_START = START_BLOCK+1
//SYS_END = SYS_START + 1200
mkpartfs primary ext2 SYS_START SYS_END
//DATA_START = SYS_END+1
//DATA_END = DATA_START + 3500
mkpartfs primary ext2 DATA_START DATA_END
//CACHE_START = DATA_END + 1
mkpartfs primary ext2 CACHE_START MAX_SIZE
//We have partitioned the memory card. Let's format them. Ignore all "Do you wish to continue" question in the next commands as we're already mentioning yes.
mkfs yes 1 fat32
mkfs yes 2 ext2
mkfs yes 3 ext2
mkfs yes 4 ext2
quit
//Now they are almost ready. Just make the newly created blocks readable by the OS.
make_ext4fs /dev/block/mmcblk1p2
make_ext4fs /dev/block/mmcblk1p3
make_ext4fs /dev/block/mmcblk1p4
//Now you get where does the blocks come in the kernel right?
exit
//You've covered up the hardest part. Let's get some coffee and cheeerssss.
PART 3: MODIFYING THE NEW OS
You've left the OS extracted in the "External OS" folder right? It's time to do some magic in it. We're gonna tell the OS to be installed in the blocks we created just like the kernel. But wait, where does the OS know before installing where it should get installed? Well, the answer hides in the updater-script in the folder META-INF > com > google > android. Navigate yourself in it. Open the updater-script file in your favourite editor ( I use notepad++ ) and modify it in the same way as the kernel.
Replace every instance of the first line with the second one:
/dev/block/bootdevice/by-name/system => /dev/block/mmcblk1p2
/dev/block/bootdevice/by-name/userdata => /dev/block/mmcblk1p3
Leave the /dev/block/bootdevice/by-name/boot as it's the fundamental block and we can't replicate it. Don't think for the /cache partition as we've already done that in the boot.img file. Now navigate to the root of the folder where you extracted the External OS. Select all files, add them to a zip file using WinRAR. Name the file to newOS.zip. Open newOs.zip and originalExternalOS.zip with WinRAR and compare them if you find any change in the folder tree. They must and they should be exactly the same. You're 80% done.
PART 4: MODIFYING THE RECOVERY
We often flash many zips including very popular Xposed and other mods to our OS right? They also look for the /system partition. So what are we gonna do? Modifying each of them? Nah. Let's modify where they get which one the /system is. The recovery. Extract the img of the recovery you're using with the same bootimg.exe. Modify exactly the same things. I.e.
Replace every instance of the first line with the second one:
/dev/block/bootdevice/by-name/system => /dev/block/mmcblk1p2
/dev/block/bootdevice/by-name/userdata => /dev/block/mmcblk1p3
/dev/block/bootdevice/by-name/cache => /dev/block/mmcblk1p4
in the following files : initrd/fstab.qcom
initrd/etc/recovery.fstab
initrd/etc/twrp.fstab(For TWRP only)
Save them. Repack. And you got your recovery-new.img and recovery-old.img. Put recovery-new.img and newOS.zip in the same folder. Now wake up, it's time for some action.
PART 5 : INSTALLING THE OS
Open cmd in the folder where newOS.zip resides. Reboot the devixe in fastboot mode. Type the following commands:
Code:
adb push newOS.zip external_sd
fastboot flash recovery recovery-new.img
fastboot boot recovery
Now your device should boot up in recovery mode. To check if everything has gone fine mount system using TWRP. Use twrp's built in file manager and navigate to system folder. It's empty? Yup. You've done a great job. Now flash the newOS.zip using TWRP and your device should boot up in the new OS. To cross check again remove the SD card and try to boot. If you're headed towards recovery or bootloop after that then it's a win. Put the SD card back again and watch the new OS to boot.
PART 6: SWITCHING BETWEEN THE TWO
Extract the boot.img from the "Internal OS" zip file and put it together with recovery-old.img. To check if your old system is untouched type the following commands in fastboot mode:
Code:
fastboot flash recovery recovery-old.img
fastboot flash boot boot.img
fastboot boot system
Your device should take you back to the old one. Surprised? Now let's make a switch between the two. There are two methods.
METHOD 1: USING FLASHIFY
Create two folders in your SD card. Put boot.img and recovery-old.img to one and boot-new.img and recovery-new.img to the other. To switch to the external OS, just flash boot-new.img as boot and recovery-new.img using flashify. Ignore reboot now dialog and reboot directly to the system. To go back, first install flashify in the new OS and flash boot.img and recovery-old.img. Easy right?
METHOD 2: USING ZIPS
I'm gonna tell you that tomorrow as I can write no more today.
More to come....
CREDITS:
justzzshadz from MIUI forum for this revolutionary concept. @iamsubhranil for adding TWRP, Flashify support and completely rewriting the tutorial.

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