Exactly the same as the Duo's used to do!  Try Daishi Kato's kernel
and/or the "invidtest" kernel.  They don't boot (mine),  but do get as far
as initializing the internal console and writing some output to it.
> 
> Anyway, once all of the files were installed on the A/UX partition, and
> I tried to run the MacBSD booter, my machine locks up. I get no
> diagnostic gray bars, and very few clues as to what's going on. The
> screen shot just before it dies is:
> 
> Booting. . . . MID_M68K executable: entry 0x249e.
> 507356 (0x0)+ 42720+96584+35916+37440 Bye-bye . . . .
> 	So I sez to him . . . . the real way that is should be is to:
> Ser Console = 0 
> 
> (and the machine dies . . . only way out is to hit the on-off switch)
> 
> When I turn the debugging option on, I get a couple of more clues. It
> tells ma that it's doing a couple of core dumps -- first of copycode() .
> . . . . . . and then of HarryO . . . .
>