does flashing a kernel ever wipe anything on the phone?

and is it ever dependent on android version?
e.g. 4.22 or 4.3

I have CWM and i've seen the option to install from zip within CWM recovery.

but is there a command with adb or fastboot to do flash the kernel? what is it?

Or do you pretty much have to install it via CWM>

2 Answers 2


No, flashing a kernel only wipes the old kernel. Generally, user-space drivers in the system image will be specific to a particular version of the kernel driver, and each kernel driver version will only work with certain kernel versions, so only flash a different kernel if you know that it was built to work with your user-space version, or vice-versa. Usually stock ROMs will only work with the kernel that came with the ROM, and third-party ROMs will say which kernels they work with.

On devices that support fastboot, you can use fastboot flash boot boot.img to flash the file boot.img to the boot partition. This is the one that stores the kernel.

  • You write "Usually stock ROMs will only work with the kernel that came with the ROM, and third-party ROMs will say which kernels they work with" <-- so some ROMS include kernels and some don't? are they flashed with the same command? and will they wipe everything?
    – barlop
    Aug 24, 2014 at 20:22
  • Also I don't know if you're familiar with CWM, so where the bootloader recovery portion is flashed with CWM Recovery, and then the option is available to install from zip. Is that the same as this command fastboot -w update blah.zip
    – barlop
    Aug 24, 2014 at 20:58
  • This site works best when you have a single question. It sounds like you want someone to explain lots of things about custom ROMs.
    – Dan Hulme
    Aug 24, 2014 at 21:26
  • The above 2 comments contain 2 questions. One is on a sentence you wrote(that's the first comment). The other(the second comment) is what I asked in my question just being more explicit. So it's not like i'm trying to throw lots of new things into my question. But if you think the original question is too big then I could split it.
    – barlop
    Aug 25, 2014 at 1:39

it will replace your existing kernel. But before that make sure your ROM is compatible with new kernel or you will end up in boot loop.In certain kernel WiFi may not work. You may have to install WiFi modules separately.

  • Is there a way to find out what ROM I am currently on?
    – barlop
    Aug 28, 2014 at 17:59

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