Hello, I try generated installation with ext4 /boot in a more modern ppc64el (Raptor CS Blackbird with Petitboot 0ef84c0 (POWER9)) and it can see and boot the generated installation. So seems only POWER8 Tyan systems that are unable to boot on ext4, It seems they (Tyan) stop making POWER soon after so there is not PNOR(bios) update after march 2016. For IBM made POWER8, possible better support and being able to boot on /ext4 but don't have one to test. Sorry for the burden for an old POWER8 by Tyan.
Have a nice day, Olivier
