Modernize kernel build for zero/rpi2/rpi3/rpi4
There are tweaks per platform, such as 32 vs 64 bit builds and which toolchain to build (64bit would use aarch64 which is not currently being built). I need to update the HW=<> option to make use of these.
The overlays and DTB's can be grabbed directly from the kernel build tree.
The build page referenced above still refers to the git repo that's been used for a while now.See: