The gemian kernels are built from the '
native' branch this would work if you were to build on device, and my test builds are built from the '
packaging7' branch. The only differences in those branches should be the crossbuilding config in the packaging branch. Please ignore the p8 branch which is a broken shelved WIP trying to update to the android 8 based kernel release.
I do a 'debuild -b -uc -us' within the checked out version of the kernel sources, which gives me a package that I can install on the device, which then does the final parts of the image making there, initramfs etc.
I do the cross building within a debian stretch lxc container as its compiler is known to work with our sources, the buster versions of the compiler sadly fails to give a booting kernel.
I've basically given up with the p8 branch as not enough of an update and so am currently working on a
mainline kernel, which at least so far builds and boots when using the latest ubuntu compilers, so no need for old lxc containers. No idea how long it'll take to become useful, quicker with more hands of course. So far its just booting to usb-uart serial console busybox, Jasper got us there. I've so far failed to get i2c or pmic devices to work, but I may have just got it to tell me the CPU core temperature.