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How'd You Manage to Get Atags Working?


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#1
ilikenwf

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I'm working on the Droid2, and I was wondering how you guys managed to get the atags working - I see you have a module for making the procfs rw and then adding your atags manually, but I was wondering how you managed to get the atags for the devices you work with in the first place. So far, I started from the kexec-mod sources, which I'm not sure it is who originally did that, but I've modded it to work and build with the Droid2/DroidX, and made a custom atags module too...

I have the following building/inserting/running for the Droid2:

atags.ko
kexec_load.ko
procfs_load.ko
kexec-tools

However, at this point, I'm pretty lost and could use some guidance in the correct direction, if someone would be willing to help me out. I've been looking through your git repos and haven't found any clues as to how you managed to build your atags3 and devtree3 files, and I'm just curious if you could maybe outline how you've managed to get these things all working so those of us in the android community with other devices that have encrypted bootloaders can use your methods to bypass things with kexec as well.

My github repos related to this:
https://github.com/i...kexec-mod-d2-dx
https://github.com/i...mod-atags-d2-dx
https://github.com/i...xec-tools-dx-d2

My posts on xda and rootzwiki:
http://rootzwiki.com...rk-with-droidx/
http://forum.xda-dev...77#post25117377

#2
kholk

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A way for doing that is extracting the atags from CDT, but that won't work because there are some others that the bootloader is passing.

Personally, I've extracted the atags using a custom kernel on my Developer Edition RAZR and dd'ed to that file that I'm writing like you see.
An idea for your device would be to find someone with an engineering device that can flash a kernel with atags support for doing the same thing!

#3
ilikenwf

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I see. That'd be a wonderful feat, especially finding someone with a developer version of the device. I guess posting around XDA and RootzWiki, and perhaps some other places would be the way to go?

The droid2 is about 2 years old, and as of yet, I've been unable to find any sort of dev device released for it. I believe atags are specific per each device, and not just each kernel, if I'm not mistaken. I wonder if I could run an atags enabled droid2 emulated device from motodev and get the atags...as long as that bootloader isn't locked as well.

#4
ilikenwf

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Do you know of a way to dump the memory and extract the atags from the dump?

#5
kholk

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This isn't as simple as dumping something from kmem... this requires a lot more than that, you can't just dump them from memory!

#6
ilikenwf

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I figured as much. I have found that older versions of kexec didn't even rely on the atags (at least as much)...I'm looking into that, per http://nesl.ee.ucla...._atags-r2.patch

#7
kholk

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Oh it's useless. Our devices are IN NEED of atags.
Booting without atags will totally fail.

#8
Nick Johnson

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A way to get the atags working is through extracting the atags from CDT, if the bootloader is passing by then may be it won't work.

#9
kholk

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Nope, CDT has got only some of the required atags... the other ones are passed by the bootloader.

Only an engineering phone (or an ugly, ugly hack that I don't even know if it is possible to do on an already running kernel) can help you get the correct atags.




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