Hi jggimi,
thanks for your reply and for the welcome!
I used to be subscribed to misc@ once, quite a long time ago. Currently I just don't have time enough to deal with high volume mailing lists on top of everyting else. So I prefer to use misc@ passively by trawling the archives. BTW, the small community is actually one of the reasons I like this place. Makes it a lot easier to keep track of things, despite the drawback of far smaller input pool.
I haven't given up, yet. Creating a bootable USB stick for OpenBSD could apparently be as simple as creating a DOS-formated 1-partition USB drive and placing either of the BOOTIA32.EFI or BOOTX64.EFI files (available for 5.9 and newer) in a directory called /efi/boot. That alone is enough to have the drive show up on the macbook's graphical boot menue (pressing 'alt' at boot). And selecting the drive does indeed start the OpenBSD EFI bootloader. So far, so good. Unfortunately that's also when the problems start. It seems the bootloader has somehow can't access the filesystem properly.
I get errors like
Code:
open(hd0a:/etc/boot.conf): Invalid argument
Code:
start(hd0a:/.): Invalid argument
I'll see if I can find out more and will report back if I make any progress.