[13:34] <ikonia> the pi zero 2 is listed as compatible/certified against ubuntu 22.04 server, I've just put a 22.04 SD card in a zero 2 and it gives me the rainbow screen. 
[13:34] <ikonia> All the documents and posts I've found on the pi forum show this as an incorrect boot file, I've checked this booting raspberry OS, and it boots fine
[13:35] <ikonia> I find it hard to believe that something that's flagged as certified on the ubuntu page would not have the right files/config in place to boot
[13:35] <ikonia> am I missing something special about the pi zero 2 ?