Build android boot image (desire)

1. Download some file
   repack-bootimg.pl
   unpack-bootimg.pl
   split_bootimg.pl
2. Dump boot.img from device
   cat /dev/mtd/mtd2 > /sdcard/boot.img
3. Un-pack boot.img
   ./split_bootimg.pl boot.img
4. Extract the ramdisk.
   mkdir ramdisk
   cd ramdisk
   gzip -dc ../boot.img-ramdisk.gz | cpio -i
   cd ..
5. Recreate ramdisk (the mkbootfs binary produced from building the Android source code)
   mkbootfs ./ramdisk | gzip > ramdisk-new.gz
   
6. Re-pack boot.img
   mkbootimg --cmdline 'no_console_suspend=1 console=null' --base 0x20000000 --kernel boot.img-kernel --ramdisk ramdisk-new.gz -o boot-new.img
   
   For Nexus One : Add --base 0x20000000 to mkbootimg command-line.
   
   (Note: the console=null command line option was introduced in the TC4-RC30 boot images to remove the root shell (TODO: add link))

7. Flashing your new image back onto the phone
   adb push ./mynewimage.img /sdcard
   (android shell) cat /dev/zero > /dev/mtd/mtd2
   write: No space left on device [this is ok, you can ignore]
   (android shell) flash_image boot /sdcard/boot-new.img
8. Reboot
   

Reference:

• http://www.cnblogs.com/shenhaocn/archive/2010/05/25/1743704.html
  
• http://android-dls.com/wiki/index.php?title=HOWTO:_Unpack%2C_Edit%2C_and_Re-Pack_Boot_Images