I encountered with console initialization issue in cpu_cons.c.

/// description ///

When NetBSD/pmax compiled from stock 1.2E source code tree is booted on
DS5000/25, machine gets stucked off right after;

  .........
  mainbus0 (root)
  cpu0 at mainbus0: MIPS R3000 CPU Rev. 3.0 with MIPS R3010 FPC Rev. 4.0
  tc0 at mainbus0: 12.5 MHz clock
  asic0 at tc0 slot 3 offset 0x0
  le0 at asic0 offset 0xc0000 priority 4: address 08:00:2b:35:10:49
  le0: 32 receive buffers, 8 transmit buffers
  scc0 at asic0 offset 0x100000 priority 5

Looking at console message carefully, obscure message below was there.

  Using PROM serial output until serial drivers initialized

/// Diagnostic and fix ///

One simple addition in pmax/pmax/cpu_cons.c caused the trouble.

#if NRASTERCONSOLE > 0
....
#endif /* NRASTERCONSOLE */

Unfortunately there is no inclusion of "rasterconsole.h", so major code
portion to detect framebuffers was accidentally not compiled in.
The time stamped as follows;

/*      $NetBSD: cpu_cons.c,v 1.15 1997/05/15 16:43:36 mellon Exp $     */

The solution is trival; this issue might be already fixed in most current
source tree; add #include "rasterconsole.h" in the file. 

Tohru Nishimura
Nara Institue of Science and Technology