I have a Samsung Galaxy S3 (international and unlocked). I recently downloaded the kernel source code from Samsung's website and have successfully compiled and now have a zImage file. My problem is what to do with it?

I have seen people saying to use fastboot boot zImage to test that the kernel works before more permanently flashing it with fastboot boot zImage zImage but fast boot wont recognise my phone. When i type fastboot devices i get nothing. fastboot reboot (i think that was it) sits there for ever waiting for the device.

I have also tried adb just to prove a point. This sees the device with adb devices (while the phone is in normal mode) but still didnt help.

I currently have the Clockwork recovery mod installed. Could this be causing issues? and if so how do i remove it?

Everything i have seen says to boo the device into fast boot mode. Is this Download/Odin mode on the S3?

Thank you


EDIT: Forgot to mention i have tried this on Ubuntu 12, OSX 10.8 ans Windows 7 with drivers installed

  • 1
    EDIT: I'm not even sure the S3 supports fastboot at all! Samsung has this download mode instead (odin/heimdall) where you need to flash stuff. If it has it: You need to boot into the correct mode, if I'm not wrong its this combo: "vol-up+home+pwr" then plug into USB. You see an alternate boot screen then (if not, search for "enter fastboot mode s3" or so). I'm not sure if the 'boot' command is supported with your S3 though (that's up to Samsung if they support it)
    – ce4
    Aug 5, 2012 at 9:03
  • Think you may be right about it not supporting fastboot. When i run adb reboot bootloader it just reboots the phone normally. In this case what is the best way to flash my custom built kernel on? fastboot looked good because by using fastboot boot zimage i could test the kernel before flashing it on. Is there another utility i can use that will give me this functionality? Thanks
    – Darc
    Aug 5, 2012 at 9:55
  • Yeah, 'fastboot boot img' is great for testing, that's what Google's lineup all support, aka. 'Google experience device'. I guess the next thing will be either heimdall or maybe kexec support (the latter is purely speculative by me, if it works it's the 2nd best thing next to fastboot boot, search for 'galaxy s3 kexec' seems like it's in use for the locked VZW S3 already!)
    – ce4
    Aug 5, 2012 at 10:02

1 Answer 1


I have ended up installing mobile Odin and just performing a recovery with the clockwork mod if the kernel kills the phone (which is all i have managed to do so far) Thanks for your help

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