I have pcvt hacks for an et4000 that will force X out and pop to a kernel
debugger virtual console.  It's very rude and nonreversible as a result,
but useful nonetheless.

I've tried doing a similar hack for a mach32 card without total success
yet (I just need to get the durned clock sync reset---I can type and I
can see funny lines at the top of video memory).

==John