[HOW-TO] Modify boot.img for LG Thrill/O3D

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Im sure a good bit of you have already figured out that there is ZERO documentation on building a boot.img for our phones. Unfortunately it is not a generic process and every device is different. So basically this is a how-to on unpacking/repacking a boot.img for flashing to the device. This will allow you to make ramdisk modifications and create a boot.img from a kernel you compiled.

Directions
First youre going to need a few things. First and foremost, I have NO IDEA HOW TO DO THIS ON WINDOWS, so dont ask. If someone does then shoot me the directions and Ill put it up here and give you full credit.

You will need a Linux distribution such as Ubuntu (you can use a live CD or run it in a Virtual Machine as well, but again, dont ask me how to run it in Virtual Machine, Ive never done it).

-You will need to download the included boot-tools.zip which includes three things: unpack-bootimg.pl, mkbootimg, and a META-INF directory for flashing the boot.img in cwm recovery.

-You will also need the stock boot.img (or a custom one if you can find one at this point :P )

-Extract the boot-tools.zip to youre home folder. Make sure both files inside can be Executed as a program by checking 'Properties>Permissions'.

-Paste your boot.img in that folder as well.

-Open up a Terminal and:

cd ~/boot-tools

-Type:

./unpack-bootimg.pl boot.img

-This will create:
boot-img.ramdisk (this is the extracted ramdisk where you can make changes to your ramdisk)
boot-img.ramdisk.cpio.gz (this is the compressed ramdisk. You dont need to touch this.
boot.img-kernel.gz (this is the actual kernel)

-Rename "boot.img-kernel.gz" to "zImage" (OR, if you compiled your own just delete "boot.img-kernel.gz" and paste your compiled zImage here.

-Now you can make any changes you want inside boot-img.ramdisk.

-Now to repack the ramdisk so it can be packaged with the kernel you need to change directories in Terminal again:

cd ~/boot-tools/boot-img.ramdisk

-Now in the Terminal type:

find . | cpio -o -H newc | gzip > ../newramdisk.cpio.gz

(This part may require some package dependencies which you may need to install (gzip)

-This will produce a new package called "newramdisk.cpio.gz" This is the ramdisk you will package into the boot.img.

-So now finally we are going to bundle it all up into a boot.img

-So again we are going to change directories in the Terminal:

cd ~/boot-tools

-Now this next part needs to be exact or it will not work. In Terminal type:

mkbootimg --kernel zImage --ramdisk newramdisk.cpio.gz --cmdline "root=/dev/ram0 rw mem=128M console=ttyS2,115200n8 initrd=0x81600000,20M ramdisk_size=20480" --board omap4spd --base 0x756e0000 --ramdiskaddr 0x81600000 -o newboot.img

-This is very fast and it produces a new file called "newboot.img"

-You can now either delete or rename the original file called "boot.img"

-Now rename "newboot.img" to "boot.img"

-Now take "boot.img" and "Meta-INF" and zip those up together, naming the .zip whatever you want.

-Now you have a flashable boot.img update.zip you can put on your SD Card and flash from CWM recovery.

I suggest unpacking and then repacking a stock kernel without modification and then flashing it just to make sure it works before you make any changes.

Barring typo's, this process does work. Ive built a boot.img with it and the boot.img has been verified by other xda-ers to fully boot up and work. If I messed something up just let me know so I can fix it! Feedback is always welcome!

DOWNLOADS
boot-tools.zip

A breakdown of the boot.img bundling code:

mkbootimg --kernel zImage --ramdisk newramdisk.cpio.gz --cmdline "root=/dev/ram0 rw mem=128M console=ttyS2,115200n8 initrd=0x81600000,20M ramdisk_size=20480" --board omap4spd --base 0x756e0000 --ramdiskaddr 0x81600000 -o newboot.img

mkbootimg: This is just the command to use mkbootimg that packages the boot.img
--kernel zImage:This defines the file you want mkbootimg to use as your kernel.
--ramdisk newramdisk.cpio.gz: This defines the package you want to use as your ramdisk.
--cmdline "root=/dev/ram0 rw mem=128M console=ttyS2,115200n8 initrd=0x81600000,20M ramdisk_size=20480": This part is specific to our device and is taken from the kernel source. This is the part that was such a mystery :P
--board: This defines what board were installing our kernel too. This may or may not be needed. But I didnt test without this.
--base 0x756e0000: This defines the kernel base address. This is also device specific.
--ramdiskaddr 0x81600000: This defines the ramdisk base address. This is also device specific.
-o newboot.img: This tells mkbootimg what to name the output file, which in this case is "newboot.img" You can change this to whatever you want.

Thanks, good write up. I have a question. I'm on mac. I have mkbootimg from ICS sources, but I have no --ramdiskaddr option. Are you using a special mkbootimg?

You can install run it through cygwin on windows and i think on a mac too. Thats what i use for my kitchen and tools...

Or you cab just make a 10 gig partition and run dual boot ubuntu... i do that too but actually use 20 gigs... it is much easier than virtual. I use cygwin the most unless its a heavy duty project.

Sent from my LG-P925 using XDA App

Dont know what im doing wrong...

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getting

"mkbootimg not found"

dont know what i did wrong...

its in the folder...

any ideas?

Cannot repack in cygwin. You must use virtual or real ubuntu install.




Sent from my LG-P925 using XDA App

Thank you eternally sir! This shall come in handy.

oh, and I'm going to be doing this on my HP 210 netbook with Linux on it. It's what I've compiled every kernel over in the Infuse forums and even Linuxbozo's CM7 Kang for myself before I moved to the Thrill.

Anyone try to complie the kernel with cm7 source? Didn't get the Tiap_drv.ko (wifi driver)

Sent from my Optimus 3D using Tapatalk

anyone?

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im running ubuntu linux...
i tried adding ./mkbootimg... (says cannot execute binary file)
i tried adding sudo ./mkbootimg... (says syntax error)
i tried sudo mkbootimg... (says command not found)
i tried a space between . and /... (says no such file or directory)
i tried adding the full file path.
i have no idea what to do...
help please.

Originally Posted by bzlmnop

im running ubuntu linux...
i tried adding ./mkbootimg... (says cannot execute binary file)
i tried adding sudo ./mkbootimg... (says syntax error)
i tried sudo mkbootimg... (says command not found)
i tried a space between . and /... (says no such file or directory)
i tried adding the full file path.
i have no idea what to do...
help please.

Did you give mkbootimg executable permissions?

Also you might try

sudo cp path_to_/mkbootimg /usr/bin

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