How to mod: boot & Recovery

Http://forum.androidspin.com/showthread.php/3973-ADVANCED-How-To-Mod-BOOT-amp-RECOVERY

[Advanced] How to mod: boot & Recovery

This is heavily based on:
Howto: unpack, edit, and re-pack boot images

Android magic
. IMG file is special (it is not regular, it has magic), it is the image file of a particle NAND partition...

1. Use Linux
2. GetMkbootfs&Mkbootimg
   • These are tools made when compiling Android OS source code
   • If you do not want to compile your own source code just download the Binaries
   • This download link is from an xda
     Forum post
   • The zip has the correct binaries but they are named"Linux-x86", Feel free to rename
   • This is just to let you know it was compiled for Linux (maybe you can find one for Windows ?) And X86 architecture

3. Get split_boot.zip from how
   To post mentioned in the beginning
4. Grab a boot. IMG or recovery. IMG (my examples will be based on recovery )-See Post #3 for grabbing these from your device
5. Split it
   • Code:

     ./split_bootimg.pl recovery.img

   • It cocould tell you that there is no Android magic... in which case this file cannot be split this way... tell us about it...

6. Examine
   • You will have two new files based on whatever file name you gave abve
   • Kernel will have "-kernel"
     • Yes this is the kernel (Compressed) for this. img
     • You have successfully extracted the kernel
     • You cannot edit these
     • You can mix and match
     • If I know the kernel from older boot works I can just use it with my Newly Edited ramdisk

   • Ramdisk will have "-ramdisk.gz"
   • Feel free to rename

7. Unpack ramdisk
   • Code:

     mkdir ramdisk_recoverycd ramdisk_recoverygzip -dc ../recovery.img-ramdisk.gz | cpio -i

8. Examine
   • In all ramdisk you will have a few folders and files:
     • Data
     • Dev
     • Etc
     • Proc
     • Res
       • Images for recovery go here

     • Sbin
       • The actually recovery binary goes here
       • Also adbd

     • Sys
     • System
     • TMP
     • Default. Prop
     • Init
     • Init. Goldfish. RC
     • Init. RC
     • Init. Yuhua. RC
     • Init. Yuhua. Sh
     • Initlogo. RLE
       

   • Obviously recovery and boot will be different
   • Compare stock ones with ones I edited
   • Use Beyond compare or meld

9. Pack-up ramdisk
   • Code:

     mkbootfs ./ramdisk_recovery | gzip > ramdisk_recovery-edited.gz

10. Back to IMG
    • Code:

      mkbootimg --cmdline 'no_console_suspend=1 console=null' --kernel recovery.img-kernel --ramdisk ramdisk_recovery-edited.gz -o recovery-edited.img

    • Use File good file names! Or you might end up with your test tries and cannot figure out what you did for each
    • Here you can mix and match kernels

11. Now flash via recovery or something
    • Only mess with boot or recovery if you break both you will have a bricked Device