[Q] [Resolved] Are kernels backward-compatible?

[kipue]

hi all!
Here s the story:
I went to flash VR 2.3 yesterday, which welcomed me with a blank screen at boot. Tried another rom, got same result.
A little scare and backup restore later, i was back on track and understood that those roms are KG3 based and a new kernel was not "recommanded" but NECESSARY
So, my question is this: if I update to KG3 Kernel, can I still run other stuff? If not, is it OK to flash an older kernel just for another older base rom?

Thanks!

EDIT:
[A]: Yes

 

[HellcatDroid]

Yes and no.

The actual kernel code itself has close to 0 changes from FW version to version.
(Though, there HAVE been some changes from 2.3.3 based ones to 2.3.4 ones).
Usually a 2.3.3 kernel works on most (if not all) 2.3.3 based FWs and same goes for 2.3.4.

However, there is more in the zImage than just the bare kernel code, there is the initial ram disk that takes care of booting up the OS.
Some ROMs depend on certain things to be or not to be in there (usually goes for custom kernels).

But there is really no problem just flashing a matching kernel for ROM/FW you're going to install.

 

[kipue]

Thanks a lot!
I just went ahead anyhow, and flashed KG3, then just let the phone reboot in VR 2.1 (which is KF2, I believe). it booted just fine, so I guess it might be, as you say, on a case by case basis.
I ll talk with VR dev so that he can edit the install instructions, which are a little misleading since he states this step is optional

Thanks for getting back to me!