I have always seen similar from my m0n0wall, and I don't run on a Soekris. It's related to CF card usage.
md0: Preloaded image </mfsroot> 16777216 bytes at 0xc0ad4c04
ad0: FAILURE - SETFEATURES SET TRANSFER MODE status=51<READY,DSC,ERROR> error=4<ABORTED>
ad0: 15MB <TOSHIBA THNCF016MAA 1.1> at ata0-master BIOSPIO
Trying to mount root from ufs:/dev/md0
As for the other problems you are having, I don't know. Perhaps the image is corrupted, or the CF card is bad.