Comment 15 for bug 2012750

One thing that bothers me regarding this report is that Kernels built for Raspbian don't need `flash-kernel` as they install themselves in right place, where their bootloader is capable to pick them up. So, if you're building from unmodified sources, you not only conflict with `flash-kernel`, but these packages probably do something in `/boot` directories that's not supported on FAT32 based `/boot` partition Debian/Ubuntu uses by default.

Your porting should remove Raspbian specific features from them, and port right method of `/boot` populating into the `flash-kernel`.