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Rooted JFv1.3, Engineering Bootloader.... now what?

I have been following the Threads since I got my G1 for about 3 weeks now. Two days after receiving it I got the OTA update from T-Mobile before I knew it I was on RC30. After DREAMIMG.nbh and very careful reading I was able to downgrade to RC29, Root - Telnetd, and install RC30 Mod JFv1.2 then JFv1.3. Finally I installed Bootloader and got the skateboarding androids.
After a couple days of reading, I took the plunge. Let me be the first to say that as a Windows XP user, alot of this information is very confusing as I am used to a Dos type system, and all of these commands made it seem a bit more confusing than it really is.
Now that I have root and bootloader I would like to start to change the boot screen and try my hand at some Linux based stuff?
Being that I use Windows XP, it is my understanding that I can run Linux using Slax? I am very computer literate, but haven't tried my hand at programming since the days of Dos and Paschal. Are their any online tutorials that somone would recommend as a starter or is the Android Software so different that it may be better to start from scratch?
Willing to learn any pointers would be appreciated.

I may be misunderstanding you but if your looking to make any modifications to the operating system itself (which is definitely needed), I would suggest having a look at the Android source code at http://android.git.kernel.org. The back-end of the platform (kernel, etc) is all written in C. The userland stuff is written in Google's implementation of Java called Dalvik. Now that you have the dev bootloader, all you really have to do is clone the official android repository, make your changes, build and flash to the device using fastboot.

Thanx Datruesurfer
After all the reading it seemed alot of work was being done in Linux but I don't know anything about that so, I could be completely off base.
At your suggestion I looked at android.git.kernal and it seems they do a good job at explaining some things, but it still makes many references to Linux and Unix.
Would programming of Git be done in linux. I see that Git is gotten using .tar files which is Linux compressed files? So is it best to try to do programming using slax or ubuntu?
Also, are things like the boot screen modified using Linux based .png or can that be done in Windows?
Let me say sorry in advanced, as I am doing this for the first time, please say stop if I am being too n00bish.

Also...I noticed ....
that the commands given in the Git User's Manual look very familiar like the commands that were given while I was reverting my RC30 back to RC29 using the Pterminal/Telnet. Can this programming with Git be done off of the G1 Phone itself?

You're in over your head dude. If you haven't programmed in these object oriented based programming methods and you know nothing of linux, then recompiling the android source like the above poster suggested is too much.
I don't mean to dissapoint or negatively comment, but really save yourself the trouble.
If you really want to though, figure out the basics of C and java programming and start reading the source.

Brutal-Force said:
After all the reading it seemed alot of work was being done in Linux but I don't know anything about that so, I could be completely off base.
At your suggestion I looked at android.git.kernal and it seems they do a good job at explaining some things, but it still makes many references to Linux and Unix.
Would programming of Git be done in linux. I see that Git is gotten using .tar files which is Linux compressed files? So is it best to try to do programming using slax or ubuntu?
Also, are things like the boot screen modified using Linux based .png or can that be done in Windows?
Let me say sorry in advanced, as I am doing this for the first time, please say stop if I am being too n00bish.
Click to expand...
Click to collapse
A Few things...
1. Android and Git are two completely different products. Git is the revision control system used by Android. Whenever one of the developers at Google makes a change to the source code they will upload it to the repository. Then people can go revision by revision to see where modifications have been made and suggest their own if they wish.
2. The part where a Linux box would be handy is actually downloading all of the files in the repository and compiling your own build. As dirr said, you probably should hold off on this until you have a better understanding of the platform itself.
3 As far as the boot image goes, the bootloader will only accept files that have been formatted specifically for it. Once you have the image formatted, you can flash it in the SPL via fastboot (the screen with the skating androids) I believe this can all be done via windows now.
4. I think I better understand where your coming from as far as modification. You should look at http://code.google.com/android to learn about how to code in Dalvik, as that will help you out much more then learning C. Once you have a good understanding of that, you can try to build from source
Hope that helps...

Thanx for the advice.
After reading about the above suggestions, it does seem that to do something simple would only be simple for someone who has all the background programming information of different platforms. This is probably why most tutorials/procedures are written so vaguely here. I appreciate the input and I will hold off and just read up on things other "more experienced" people write about here. I have a basic understanding of what is happening, but the "language" is so complex. Maybe in baby steps I will learn, since it appears that on this forum "Android" is fairly new. And while I am watching what is happening here, I will get java for dummies or bone up on Dalvik and start reading and practicing. Thanx for the help guys, and thans JF, Koush and all the other senior members for the RC30 Mod. At least I have the skateboarding Androis

Load a different OS from the SD card? (MeeGo)

Hi,
I know there was done some work on dualbooting the HTC Dream, enabling you to launch a different OS of the SD card.
What exactly is needed to accomplish this? And was the methods used able to load a different kernel alltogether, or just lanch another useland using the kernel from your current ROM?
I have both a Dream and a Desire, and would like to try and get Meego running on one of them. (Maybe finding my way on the Dream, which is not my primary phone anymore, and then on the Desire when I have figured it a bit more out.)
MeGo uses the 2.6.34 kernel, which I believe several Froyo ROMS use too.
The first thing I will do, is to try to run it with minimal modification to the kernel found in an existing Dream ROM, o avoid adapting the Meego kernel to support the neccessary hardware, as the ARM-release is made especially for the N900, and probably doesn't have that wide a hardware support.
But where would I change the kernel to boot? I guess it is not really possible to modiy the bootloader in the device directly (uboot sure would be nice ), so I guess it has to be done in initramfs or similar? Not really familiar with how phones do this.

thats wt i wanted to try on my cliq too! Do u have the rom for meego?

There is no ROM of MeeGo, which is why i need to load kernel/userland from SD card. I have asked for the ARM-release of MeeGo here, but the reply wanæt very helpfull.

[Q] ROM's, Kernals, Recovery's and ROOTING?

Hi Fellow old and New Devs,
The title suggests it all. I have four questions that I think ALL newbies want to understand. I would try and explain them, but as I am just coming out of the newbie stage, I'm sure people would prefer an answer from a experianced Dev.
When answering a question please put the Question Number. Feel free to answer only one or two of the questions, I'm sure other people will cover your missing fields of knowledge.
Here they are:
1. What is rooting? Can I root my device (HTC Buzz Wildfire) and keep the stock interface? Will I loose my data?
2. What do all these Dev's mean by Recovery? What are they, why are they needed?
3. What is a ROM? Do I need to be rooted for a custom ROM? How can you trust them? Will I loose my data when installing a custom ROM?
4. What is a Kernal? How are they Different to ROM's? Should I change from the stock Kernal?
I know this is a tall order and you could write a book on the topic, but please could you write a short (a couple of sentaces will do) paragraph on each question you choose to do.
When we get enough understandable answers I will edit this post publish the Final answers for other newbies in the future.
Also feel free to enter the poll! As this is a Dev site I presume one of the options will have the most votes but we will see....
Cheers for any contribution in advanced.
th3ant

th3ant said:
Hi Fellow old and New Devs,
The title suggests it all. I have four questions that I think ALL newbies want to understand. I would try and explain them, but as I am just coming out of the newbie stage, I'm sure people would prefer an answer from a experianced Dev.
When answering a question please put the Question Number. Feel free to answer only one or two of the questions, I'm sure other people will cover your missing fields of knowledge.
Here they are:
1. What is rooting? Can I root my device (HTC Buzz Wildfire) and keep the stock interface? Will I loose my data?
2. What do all these Dev's mean by Recovery? What are they, why are they needed?
3. What is a ROM? Do I need to be rooted for a custom ROM? How can you trust them? Will I loose my data when installing a custom ROM?
4. What is a Kernal? How are they Different to ROM's? Should I change from the stock Kernal?
I know this is a tall order and you could write a book on the topic, but please could you write a short (a couple of sentaces will do) paragraph on each question you choose to do.
When we get enough understandable answers I will edit this post publish the Final answers for other newbies in the future.
Also feel free to enter the poll! As this is a Dev site I presume one of the options will have the most votes but we will see....
Cheers for any contribution in advanced.
th3ant
Click to expand...
Click to collapse
Okay, from the best of my understanding, here we go:
1: Rooting. To understand this, we must consider a computer, running linux, windows, or mac. In windows, the "Administrator" account is similar to the root account in linux and mac. Basically if you have root privileges in a system, you can modify every part of the filesystem, as well as perform any tasks the system is equipped to handle. Basically achieving root on an android device means that you can unlock the ability to flash roms, mod, and otherwise hack your device any which way you like. Nearly every model of android device has been rooted, so in most cases, yes you can root XXXXX phone. Also, since you're just gaining privileges, you can root without losing any data, apps, or settings.
2: Recovery. This is a long standing concept in SoC/Embedded device hacking. Basically it is a minimal operating system that performs some very basic, but very important tasks. The reason for it is so that you can write to the necessary areas on the NAND, which would be "busy" while android is booted. This offers a way to access the necessary partitions and write data to them while the data is not being accessed. It's also useful for backing up your NAND. Hence the name "nandroid."
3: ROM. By definition, it means "Read Only Memory." This is a chip on the board. ROM has evolved over the years. It started out as a chip that was sensitive to UV light. The earliest ROMs were "flashed" to a device by stenciling out the pathways and exposing the chip to UV radiation. Nowadays, we have fancy EEPROMs instead, which stands for Electronically Erasable Programmable Read Only Memory. This means that you can "flash" the chip by means of software, namely via Recovery mode in our case. Different ROMs have different features. They are all variations on source code made available by AOSP, or the android open source project. Some projects have their own code tracking, such as CyanogenMod. In most devices, you must be rooted to be able to install a ROM, however it is not explicitly necessary. A bit vague, I suppose. Specifically the tablet I own, the WITS a81e, you can flash a ROM to it just by putting the correct files on the TF card. This is not very common with phones, however. Flashing any rom that is not just a newer version of your current ROM will require a full format. For instance, if you have cyanogenmod and switch to a Sense or Blur ROM, you must format, but if you update from CM6 to CM6.1 you will not need to wipe. How can you trust ROM's? Well the best way to know is to either roll your own, or go with CyanogenMod, as their source is freely and easily available for scrutiny and improvement, along with a nice changelog tracker.
4. Kernels. A kernel is basically the most low level part of an operating system. It interfaces directly with the processor and provides all instruction for operation. Linux is technically not an operating system, it's a Kernel. The different distributions have the Linux kernel, and use their own different User Interfaces. Different kernels in android devices can allow you to overclock. There are many choices in kernels, and the features they offer. Some features are BFS/CFS which is the priority scheduling of processes. Some kernels allow you to charge your battery differently and conserve life. These are often called battery kernels. Also, some kernels unlock extra multitouch points in certain devices. There are different versions of the linux kernel, with many improvements with each iteration. Currently, the latest kernel available that I know of for android devices is 2.6.37. The froyo default kernel was a 2.6.32. I wish I knew a bit more about kernels, however this is about all I know. Perhaps someone could help us out and expand on this a bit?

Brilliant answer not too complicated... let's see what others say....
Sent from my HTC Wildfire using XDA App

What he said...
Pyroboy1080 well said...
That pretty much covers it.

thx for the infos..

Agreed. Thanks for using the poll!

nothing to add on that, as we used to say "merci beaucoup"

Can't ROM
Gotta be something stupid......
Can't install 2.2 or 2.3. Tried two different ODIN flashers. When I do the reset I do not get the triangel with downloading in the center. I'm rooted, Have ROM Manager, Superuser, Root Explorer, Super Manager, I'm unlocked.
I have Android SDK, Congnitive 4.1, NPS, Samsung Kies,SGH I897 USB Drivers, What else? I think I have it covered. In any case I never get the download . Even if I do a "ROM Manager Install fron SD Card, the result is a screen, blue at top and yellow at bottom with the last line saying "Installing Multi- CSC. I can let it run all night, no change in ROM. Does the Captivate sold by ATT have some kind of block or filter keeping me from updating?
Current firmware is 2.1 update 1, baseband I897UCJH7, Kernel 2.6.29 [email protected] #2, Build ECLAIR.UCJH7
Thanks

To better answer your question, I first need to know what type of device you're using...
fxstsb said:
Gotta be something stupid......
Can't install 2.2 or 2.3. Tried two different ODIN flashers. When I do the reset I do not get the triangel with downloading in the center. I'm rooted, Have ROM Manager, Superuser, Root Explorer, Super Manager, I'm unlocked.
I have Android SDK, Congnitive 4.1, NPS, Samsung Kies,SGH I897 USB Drivers, What else? I think I have it covered. In any case I never get the download . Even if I do a "ROM Manager Install fron SD Card, the result is a screen, blue at top and yellow at bottom with the last line saying "Installing Multi- CSC. I can let it run all night, no change in ROM. Does the Captivate sold by ATT have some kind of block or filter keeping me from updating?
Current firmware is 2.1 update 1, baseband I897UCJH7, Kernel 2.6.29 [email protected] #2, Build ECLAIR.UCJH7
Thanks
Click to expand...
Click to collapse

didn't know where to ask this?
hello, everyone..
i have some questions, i'm hoping some of you can anwser.
I used unrevoked to root my htc desire. after that, I used alpharev to gain s-off.
everything went fine, i got the joker, the white screen that lets me pick different options..
now Í tried all those options, nothing works.
I've been searching all night for a solution, and it seems my recovery boot and rom are missing? and what I came across is installing ANDROID SDK tools, and then run fastboot to recover an image. So I installed SDK tools, but fastboot doesn't run, it says some .dll driver is missing. in the platform-tools map is that .dll driver, should i move it?
Can someone get me a step by step tutorial on how to make my desire work again? Im kind of a noob, all I needed was to make a screenshot..
Thanks in advance, it would be appreciated so much..

Pyroboy, I'm using a Samsung Captivate. In another thread someone lead me to "All in One Toolbox". The other stuff is just stuff. That allowed me to install my ROM.

[Q] Creating Custom ROM

Hello, I'm new to all this Android stuff (I don't even have a phone yet, but its on it way)
I have been reading up on custom ROM creation but there are some things I don't quite understand.
Let's say I have a phone in Android 2.3. I want to create an Android 4.0 ROM to put on the phone.
Now... to compile Android 4.0 I need the drivers for my phone (which I doubt I will ever have access too since its only a cheap Android with a MediaTek CPU)
So I have a 2.3 ROM that contains all the compiled drivers and the Android 4.0 source code.
Is it possible to compile 4.0 and replace the zImage (if I'm correct) with the 2.3 zImage. From what I have read, that's where all the drivers are stored.
I guess its not that simple since I also think the zImage contains the OS. If so, is it then possible to extract the zImage and replace the invalid driver files in 4.0 with the correct drivers from 2.3?
Also, I think my phone will arrive with an annoying UI, is it possible to just get any 2.3 ROM (that doesn't have an annoying UI and shares the same CPU as my phone) and replace the zImage in that with my phones 2.3 zImage?
Sorry, if my questions are stupid but this is all new to me. I've tryed to read up on this but nothing is straight to the point.
Thanks

Anyone there?

try out some roms first. see what you like and dont like. it'll probably give you a better idea for how you would make your own rom.

I don't think you could just port an entire zimage to ICs and say it will work (it might not even compile i think). It won't work. You could probably take some drivers' code (screen, speaker, etc), modify them a bit so it compiles, and test to so if it works. You more than likely have to modify the ICS code also so it works. And the zimage is just the kernel no? And the kernel really only has to do with low level system processes, drivers, etc. I think UI's and such are more fitted in frameworks and such.
Personally if it was so easy to port ICS by simply replacing the zimage or file with another, ICS would have been ported to many devices, fully working, by now.

Kailkti said:
I don't think you could just port an entire zimage to ICs and say it will work (it might not even compile i think). It won't work. You could probably take some drivers' code (screen, speaker, etc), modify them a bit so it compiles, and test to so if it works. You more than likely have to modify the ICS code also so it works. And the zimage is just the kernel no? And the kernel really only has to do with low level system processes, drivers, etc. I think UI's and such are more fitted in frameworks and such.
Personally if it was so easy to port ICS by simply replacing the zimage or file with another, ICS would have been ported to many devices, fully working, by now.
Click to expand...
Click to collapse
Yeh, but my problem is I don't have the drivers for the phone. I just have the stock ROM that come with it.

Is not that simple. I am 99% sure that you can't do that.

The phone I'm getting has a horrible theme on it. Its running Android 2.3
I have the ROM for a very similar phone (also using Android 2.3), uses the exact same CPU so it should be compiled using the correct platform.
Is it possible to use that phones ROM but replace it with my phones Kernel and .prop (so it has all my phones drivers and settings etc...)?

the hard work required in making a custom rom
I think you can take from the stock rom and compared with existing custom rom
but some sources are not shared freely as an example Tegra
CMIIW

I will mess about with the ROM when I get my phone. Hopefully I wont brick it...

I too am fairly new to android. I spent a couple weeks reading and watching TONS of youtube videos on how to ROOT and Unlock my bootloader. My best advice from one n00b to another would be to do the same. In particular...research how to do it on YOUR phone. Also, Roms are device specific. I recommend you finding the forum here on XDA for your phone and read up on whatever ROMS are available here. This might not be the ONLY place to find ROMS, but this place simply rocks! Once you get your device rooted and if necessary, your bootloader unlocked...you can easily try out any ROM without much fear. Just make a good backup...make sure you also have a factory recovery image too...just in case. For backups...if you install and use Clockwork Mod (CWM) you can use the nandroid backup it offers. I bought Titanium backup from the market and used it to do a full backup before I started...it backs up to dropbox even, which was a nice feature for me. Extra safety so incase I hosed my external SD card which had my backups...I could easily retrieve a backup ANY place that had internet access. Lastly...get ready to have some FUN! Flashing ROMs is VERY addictive!! :-D

Ok, Thanks. I will see what I can do then.

Linux on TF300?

Hi Guys,
I am looking for linux working on TF300T, is there anyone who has anything working? I am planning to start with linux for TF300T, I want to know if anyone has tsarted, how do I collaborate and not reinvent the wheel. I have questions regarding what bootloader to use, lilo / grub / u-boot as Nvidia has a ubuntu distribution for its chip, which uses U-boot. Lot of questions can any dev please reply, so I can think of a place to start.
Thanks
Sent from my ASUS Transformer Pad TF300T using xda premium

So far I'm quite satisfied with my android linux device ( with some chroot debian thrown in for good measure).

I'm wondering about this as well. I've got some experience with linux (servers) but not a clue how the android boot structure works.
I have found this though: http://eeepadhacks.net/transformer-hacks/how-to-install-native-ubuntu-on-eeepad-transformer/

Not to spam, but does anybody have *NIX running on the TF300? I'm very interested since Android is based on the Linux kernel, so I would think that there is some form of *NIX running on this device, since I'm hoping that there is so I could actually use this as a "laptop" for my school work.

I am fairly sure that Android is Linux. However what people are missing is the GNU environment (and tools) that the majority of the Linux distributions have. You can see that Android/Linux is vastly different from GNU/Linux.
Thus, I think the question becomes something like "Is there anyone who has GNU/Linux working on the TF300T?"
There are two methods I know of to get GNU/Linux running on Android: Chroot and Dual boot.
* The chroot method runs the linux services and programs inside Android, but is available for basically most devices.
* The dual boot method works (mostly) with the original transformer (as Citruspers has mentioned)
I myself don't have a tablet yet, but I have been looking to get a TF300T (if I don't buy a TF700T - but that is for another discussion) on the basis I can dual boot Android with a GNU distribution.

Linux = kernel. Android runs a Linux kernel. Android IS Linux.
The two biggest differences between Android and "ordinary" Linux distributions are libc (called bionic in Android) and the lack of a real X server on Android (there is a Java version at https://code.google.com/p/android-xserver/ , but it's wayyyy too slow to get anything done (it's still awesome, though). It needs to be implemented in a lower level language).

/dev/void said:
Linux = kernel. Android runs a Linux kernel. Android IS Linux.
The two biggest differences between Android and "ordinary" Linux distributions are libc (called bionic in Android) and the lack of a real X server on Android (there is a Java version at https://code.google.com/p/android-xserver/ , but it's wayyyy too slow to get anything done (it's still awesome, though). It needs to be implemented in a lower level language).
Click to expand...
Click to collapse
Any chance Wayland will work any better with Android than X? I wouldn't mine tossing a *box or even WindowMaker on my tablet (assuming they play nicely with Wayland).
Edit: Yes, I realize that Wayland barely works with GNU/Linux as it is, and it probably won't be usable even on the desktop until I'm upgrading to a new tablet. I'm not expecting it anytime soon.

Extracted from http://androidroot.mobi/2012/06/17/ubuntu-on-the-transformer-prime-preview/ regarding Ubuntu on Prime 201...
It has been a while since the last post about ubuntu on the Transformer Prime. This post is going to explain a few of the new changes, and show a video preview of the system in action.
There have been a few changes since the last update:
3.1.10 Kernel -- Asus don’t update the kernel while remaining on the same android major release, so they won’t update the kernel until at least Jellybean, but we have worked really hard to bring us up to the latest kernel. This has given us the ability to use the latest Tegra ULP GeForce binary from nvidia and maintain acceleration with the latest releases.
Linux as a bootloader -- With some work to the process we have managed to get kexecboot working to give us a boot menu that will boot not only multiple kernels from eMMC, but also to allow booting from USB, SD, and MicroSD. At this point in time the guest kernel also requires two patches, one for speed (it is really slow to boot without this patch, 30sec-5minutes) and the second to copy ATAGS, this second patch is important so that the new initrd and command line get used.
Ubuntu 12.04 LTS -- The last image was 11.10 which is a little less stable. 12.04 has a new gpower applet which can read the battery levels. 12.04 also includes the mtrack driver allowing the trackpad to work. The biggest change with the new image is the use of armhf over armel.
LVM -- Turning mmcblk0p8 (/data under android) to an lvm volume group has allowed both android and ubuntu to coexist on the eMMC without needing nvflash for reformatting. This however does require a modification to the android initrd to reflect the change and for the lvm binary to be included so it can mount /data. Ubuntu natively supports booting from logical volumes.
Click to expand...
Click to collapse
I know, I know this is TF300 forum, but it seems the TF300 is more similar to the TF201 than the primitive TF101

EndlessDissent said:
Any chance Wayland will work any better with Android than X? I wouldn't mine tossing a *box or even WindowMaker on my tablet (assuming they play nicely with Wayland).
Edit: Yes, I realize that Wayland barely works with GNU/Linux as it is, and it probably won't be usable even on the desktop until I'm upgrading to a new tablet. I'm not expecting it anytime soon.
Click to expand...
Click to collapse
Good call. While we're on the desktop managers, how about KDE's entry in the mobile device space? Aren't they supposed to have a native linux tablet going to retail soon?

My chroot runs smooth but native would be fun! Hope someone get's this working.

I hope once the guys at androidroot.mobi release the installer package for Ubuntu for the Prime, it works on TF300.

I'm looking for the ubuntu on my tf300t too.
Its strange, I know Ubuntu showed off dual booting kernel for android devices like 6 months ago. You basically docked your phone and it became a full Linux desktop with unity. But haven't heard anything since, only a page on Ubuntu's site for hardware manufacturers.
http://www.ubuntu.com/devices/android

(Sorry to revive this old-ish thread, but I didn't think it was any better to start a new one and clutter up the forum)
It seems that no one gave an honest shot into loading linux NATIVELY (not via the "linux on android" project). The original poster mentioned being interested into giving it a shot -- so how things are going on your end aditya?
I am by no means an Android rom developer, hacker, or even linux hacker, but I started my first steps into it, I thought of getting things done by this method:
Instead of wiping the whole recovery partition like the guy on the TF100 did, i'd use a somewhat altered version of a recovery where I launch a recovery-like menu where the user can continue to the "real" recovery, or boot linux
(Basically, I got myself a version of the /sbin/recovery, which has its menus altered to only show "linux" or "recovery". Selecting recovery launches the real /sbin/recovery)
If the user choose to boot linux (which could be automatically selected after a timeout), that's where kexec steps in and boots the right kernel and linux pre-baked image files
I got all that covered (my pre-recovery menu is 90% working, custom kexec'd kernel w/kexec binaries packed into my recovery), but i forgot a small detail: There is no way I could load a full 1Gb Ubuntu image into memory, (in other words, what does happen to the old mount points managed by the first kernel when I load the second kernel via kexec? Gets broken, right?) So I came into realization I would need an initial ramdisk to mount my mmc so I could finally load/mount my main 1 Gb image file.
Honestly, for somebody not into hacking, I am under the impression this is getting out of hand. This could work, but I heard we could have nvflash fully working (read: re-paritioning coming our way, just like for the TF100 where there's linux natively on its own partition).
Is there anybody else trying to do such things like I do? I might also need a reality check on what i'm doing-- altough it seems the right way to me now

Linux and GNU
It's true, Linux is the OS kernel, but with the word Linux you can also mean the GNU/Linux environment with the kernel and all the applications running on top ("The gimp" or "Libre Office" for example).
Should be nice to have a GNU/Linux system running on a tablet device; I read that Canonical (Ubuntu) is working on a project for multi-core devices but I don't know about the development stage.
/dev/void said:
Linux = kernel. Android runs a Linux kernel. Android IS Linux.
The two biggest differences between Android and "ordinary" Linux distributions are libc (called bionic in Android) and the lack of a real X server on Android (there is a Java version at .... , but it's wayyyy too slow to get anything done (it's still awesome, though). It needs to be implemented in a lower level language).
Click to expand...
Click to collapse

Trying to make this work too.
I have a basic changeroot with gentoo and compiled a kernel and initrd. I wanted to try it out using fastboot (fastboot -i 0x0b05 -c real_root=/dev/sdb1 boot kernel-genkernel-arm-3.3.8-gentoo initramfs-genkernel-arm-3.3.8-gentoo) but it doesn't even try to load the kernel. I get an error 0x120000 on the screen of the TF300. I googled a bit and found out that the TF201 has the same problem, you have to flash a boot image.
How can I make a boot image using the gentoo files? I looked into abootimg but it seems it won't work. At least it won't split up the original images, so I fear it uses another format. Has anybody tried mkbootimg?

AEblefisk said:
I have a basic changeroot with gentoo and compiled a kernel and initrd. I wanted to try it out using fastboot (fastboot -i 0x0b05 -c real_root=/dev/sdb1 boot kernel-genkernel-arm-3.3.8-gentoo initramfs-genkernel-arm-3.3.8-gentoo) but it doesn't even try to load the kernel. I get an error 0x120000 on the screen of the TF300. I googled a bit and found out that the TF201 has the same problem, you have to flash a boot image.
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Click to collapse
I only know a part of the story here, but here's my findings so far. I never got "fastboot boot" to work on my TF300, always giving me that 0x120000 error. I am under the impression (I MAY BE WRONG) that "fastboot boot" requires a more devloper friendly device (think HTC G1, GNex, anything Google branded).
That being said, I am curious why you wrote "real_root=/dev/sdb1" as your kernel parameters
AEblefisk said:
How can I make a boot image using the gentoo files? I looked into abootimg but it seems it won't work. At least it won't split up the original images, so I fear it uses another format. Has anybody tried mkbootimg?
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Personally I was able to look at how a recovery image was used and flashed onto a TF300. Without going into the details, I looked at how xplodwild's recovery was being made, and hacked around that recovery to use my own (basically trivial modifications from his).
To flash my image files, I am using "fastboot flash recovery" with my own recovery, which is basicaly a mkbootimg based image file like you said (you were on the right track), but wrapped around in a BLOB file format (using blobpack / blobunpack, see this xda thread).
So to answer your question, the only way I found so far to boot my custom kernels and init rootdisks is to flash it onto the device outright.
BTW: if you were to look at a pre-baked img file, (or, if you had no idea whats the file contents like), you could load the file into a hex editor (I use 'hexer' on ubuntu/debian, thats a command-line one). If you see "SIGNED-BY-BLOB", thats a blob file (a nvidia tegra and/or asus file format). If you see something else (usually starting with "ANDROID.."), thats usually something you can either mount or unpack using linux natively (most probably with "mount -o loop file /mnt/mountpoint")
EDIT: Slightly off topic, but still for AEblefisk: if you compile your own kernel, i suggest turning on activating the framebuffer tux logo option. More importantly, you could as well try and activate the framebuffer console too, however apparently "fbcon is broken on 2.6.39.4", so says Rayman. But at least, you'd get a hint that your own kernel is loaded and running if you see 4 tuxes on screen (one per core)

Thanks for pointing me in the right direction.
Now I managed to make a blob with the gentoo kernel and ramdisk. It flashes sort of OK with fastboot, sending in 2 seconds, but the write time is 0.016s and it seems nothing is written. I boot into Android when I reboot. (I'm flashing to boot, not recovery). Maybe I'm missing some offset or blocksize parameters?
bilange said:
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That being said, I am curious why you wrote "real_root=/dev/sdb1" as your kernel parameters
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EDIT: Slightly off topic, but still for AEblefisk: if you compile your own kernel, i suggest turning on activating the framebuffer tux logo option. More importantly, you could as well try and activate the framebuffer console too, however apparently "fbcon is broken on 2.6.39.4", so says Rayman. But at least, you'd get a hint that your own kernel is loaded and running if you see 4 tuxes on screen (one per core)
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The real_root is for the gentoo initrd to find the real root filesystem on microSD. I have no idea if it will turn out to be mmcblk1p1, sdb1 or something completely different. I'll probably have to correct that once my initrd boots.
Yes I'm definitely trying to make the framebuffer logos work. Seeing that lineup of 4 tuxes is a goal in itself
I'm using 3.3.8 in gentoo so I hope fbcon is fixed.

AEblefisk said:
Now I managed to make a blob with the gentoo kernel and ramdisk. It flashes sort of OK with fastboot, sending in 2 seconds, but the write time is 0.016s and it seems nothing is written. I boot into Android when I reboot. (I'm flashing to boot, not recovery). Maybe I'm missing some offset or blocksize parameters?
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Click to collapse
I never touched boot so far to tinker around Linux booting, for the simple reason we never use the recovery partition except to flash/nandroid backup (which I rarely do), plus it gave me with Android booting if I dont press the volume button on startup. As far as development went, I think this was a win/win situation, although lilstevie (the guy who did make Ubuntu boot natively on his TF101/200) told me to "never touch recovery, flash boot instead", he was most probably talking about deploying our custom OSes to the world to use.
Now i'm kinda lost as to why the regular Android boot is being shown up. Having 0 experience with the boot partition (which i thought was similar to recovery), i can't really help you. Maybe you should get on freenode into the #asus-transformer and ask around (Don't let the numbers of nicknames scare you, this is a low activity channel, but the most knowledgables people are hanging in there. Just be sure to do your homework (aka Google etc) before asking, you should be fine )
As a sidenote, you should probably use some (most?) of the kernel parameters used in /proc/cmdline from a live Android OS. Most specifically the "tegraboot=sdmmc gpt gpt_sector=..." part. This makes sure your kernel reads the partition table at the right (unusual) location instead of reading where ever it was on a regular system (the first 512 bytes of the drive? don't quote me on this). I suppose this doesn't prevent the kernel from booting, but it will make the SSD partitions visible from your OS.
AEblefisk said:
The real_root is for the gentoo initrd to find the real root filesystem on microSD. I have no idea if it will turn out to be mmcblk1p1, sdb1 or something completely different. I'll probably have to correct that once my initrd boots.
Yes I'm definitely trying to make the framebuffer logos work. Seeing that lineup of 4 tuxes is a goal in itself
I'm using 3.3.8 in gentoo so I hope fbcon is fixed.
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Would that be a 'vanilla' 3.3.8? I'm asking because, in case you don't know, I think you can't have much success using the regular kernel from kernel.org, and hope it will detect all the devices (specifically touch, sensors, wifi, gps(?), etc). It will maybe boot (your guess is as good as mine), but it will surely lack a few things here and there. That's why there are a ton of devices specific github kernel code base here and there: it's basically a 'stock' kernel source code, with the constructor's additions to make their various devices work, with community enhancements on top of all that. I may be wrong on the following (if there are any veterans reading this, feel free to call me a noob and point me to the right direction), but if you try to compile ASUS' kernel source code for the TF300, funnily enough everything compiles silently UNTIL it gets to the Tegra parts where it gets noisy with over 9000 warnings all along (but it compiles). That led me to believe that 1) NVidia or ASUS are lousy coders and 2) They added (most likely) OR modified a bunch of code to the stock kernel tree to make it 100% functioning on their devices.
All that wall of text only to say that I assume that the broken fbcon issue is most probably due to either ASUS/NVidia additions to the kernel code, or a bug from the 'stock' kernel code, and i'm assuming it was fixed in later versions (which lacks device's constructor modifications then again).
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Offtopic: it seems ASUS has released the kernel source code for TF300 for their JB update! Compile all the things!! (And hope fbcon as been fixed so I can see something out of the screen)

I'll definitely do my homework now I'm worried I may have flashed some other place than boot, since Android is still booting, so now checking all corners of the tablet is on top of the agenda.
I know some things may not work with a vanilla kernel, but I was hoping enough would work for it to boot. Then I could worry about the rest afterwards. Maybe using the JB kernel source will be easier, but I don't know how much has been changed in android which is used in linux. I suspect Google has worked more on modifying linux for android use than ASUS has worked to make their hardware run in android. Another option is to work on what Nvidia has published.

Now I'm getting more experienced. I hope I get some real progress before I brick it
It turned out I wasn't writing anything to flash. It seems the first blob(un)packing tools mentioned in http://forum.xda-developers.com/showthread.php?t=1697227 aren't working (for me on my tab anyway). But when I tried the BlobTools2 with the blobpack -s option my resulting linux blob was written to flash (using fastboot -i 0x0b05 flash boot boot.img).
Unfortunately my gentoo linux kernel wasn't any good. I never got past the first Asus logo and on top of that CWM recovery couldn't restore Android. CWM went through the motions but nothing booted. I had to flash the stock blob, then I got my Android back.