My guess is that the Linux EXT2 disk somehow is being seen as the first OpenBSD drive wd0. In other words for OpenBSD the drive number has changed
You can boot the OpenBSD kernel from the original drive which used to be "wd0", but that now is "wd1". But the "/etc/fstab" on what is now "wd1" still refers to "wd0", which happens to be the Linux EXT2 disk. That is why you you are being dropped into fsck_ffs.
This what I have on this box.
Code:
cat /etc/fstab
/dev/wd0a / ffs rw,noatime,softdep 1 1
You see that the drive 'wd0' has been hard coded. If this disk would become wd1, the "fstab" contents would still try to mount the "/" filesystem from drive "wd0".
Maybe you can play with the BIOS and change the drive numbering, so you OBSD disk still stays the first disk.
Or edit the "/etc/fstab" and change the "wd0" references to "wd1".
You can interrupt the OpenBSD boot by pressing the spacebar a few times and typing the command in blue to find out some disk numbering information
Code:
Using Drive: 0 Partition: 3
reading boot.....
probing: pc0 com0 com1 apm mem[639k 255M a20=on]
disk: fd0 hd0+
>> OpenBSD/i386 BOOT 3.02
boot> machine diskinfo
See
boot(8)