PC Engines APU2 Install trouble

i’m trying to install ipfire-2.25.x86_64-full-core150.iso to my APU2 via serial

i’m using putty and can access the bios, but ipfire wont boot

does anyone here know how to access the secret serial console mode?

i’ve tried down, enter…
and i’ve tried down, down, enter


to enter the super secret serial install…
its down, down, down, enter, down, enter


this sounds like an issue with the baud rate of that serial link. Have you tried setting it to 115200 bits?

Thanks, and best regards,
Peter Müller

No. It is a bios issue on the APU2. It redirect the Video output (INT10 call) to the same serial port so every character is printed twice. If you enlage the window to some more chars it is easier to read.