Vmlinuz changed UEFI boot display resolution

I used to have a UEFI boot animation with my manufacturer logo and spinning circle in full resolution (as opposed to BIOS before).

After I installed a vmlinuz / rescue image, I only get the nice logo on RESTART, but not in full resolution (native resolution).

On POWER ON/BOOT, I don’t get the logo at all, but a completely gray screen with 3 little white squares.