I had a go at upgrading the bootblocks on my RiscPC, but must be missing
something. I grabbed the necessary bits out of sys/arch/acorn32/stand, ran
the new bb_netbsd for ADFS::5. When I run !BtNetBSD, I get

  Unknown partition type
  Bombing out...
  10

?! Now of course the old boot loader isn't happy either giving

  Address overflow
  606060

when trying to run the unixfs module.

Any suggestions on what to try next?

Cheers,

Patrick