I would like to edit the init.rc in an i9300. I understand that editing the file as-is will not work as the file is reloaded from the boot image's ramdisk upon every bootup. After some googling, I read that I have to unpack, edit and repack the boot image. I came across the following link: http://android-dls.com/wiki/index.php?title=HOWTO%3a_Unpack,_Edit,_and_Re-Pack_Boot_Images

However, upon trying out the first command "cat /proc/mtd", I realize that my i9300 doesn't even have a /proc/mtd, so I'm wondering if any of the instructions there apply to this device.

/dev/block shows mmcblk0p1 to mmcblk0p12, but I'm not sure which one is the boot image. From my googling it seems that mmcblk0p6 is the recovery image though.

How can I edit the init.rc in this device?


  • 1
    What do you want to achieve by doing this? If you want to mount another thing or remount a filesystem, you can use init.d script support. Thats far more easy and will let you execute scripts on boot.
    – Peter
    Commented Feb 15, 2013 at 8:27
  • I wish to start a native service at boot, which is a cross compiled ARM binary. Commented Feb 20, 2013 at 2:19

1 Answer 1


You have two choices here:

  1. Edit the stock kernel (or the kernel you're using) to enable init.d support or edit the init.rc
  2. Use a custom kernel with init.d support already enabled.

I would suggest the second option as is far more easier to achieve. Once flashed a kernel with init.d support, you can add all the scripts you want to the folder that will be executed at boot time. The folder is located in /etc/init.d and all scripts inside that folder will be executed in order.

For example, if you have:

  • /etc/init.d/10-startup-daemon
  • /etc/init.d/50-mount-extra-partition

They will be executed in the same order I've typed them. You can change the order by changing the number at the begining of the file.

  • Thanks. I ended up unpacking/modifying/repacking the ramdisk in order to modify the init.rc to start the service I wanted. Commented Feb 21, 2013 at 7:21

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