[HOW-TO] Modify boot.img for LG Thrill/O3D
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.
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:
-This will create:
(this is the extracted ramdisk where you can make changes to your ramdisk)
(this is the compressed ramdisk. You dont need to touch this.
(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:
-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:
-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!