>                              I tried setting output-device to
> /sbus/cgsix:forcemode, just in case it worked for framebuffers too, but
> no joy.

Normally, I'd have thought that:

  setenv output-device screen:r1280x1024x76

would work.  Maybe you could be more explicit and set the slot number too.
You could try:

  devalias cgsix0 /iommu/sbus/cgsix@0,0
  setenv output-device cgsix0:r1280x1024x76
  setenv use-nvramrc? true
  nvstore
  reset

You'll need to replace the "cgsix@0" above with the correct SBUS slot
number that your card is in:

  cd /iommu/sbus
  ls

However, I'm not sure that this will work given the rest of your message.
Maybe that ROM version doesn't like the type-3 keyboard at all.  Can you
get monitor output by setting the input to ttya and the output to screen?

J

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