I screwed up the zs_unit values in sparc/dev/zs.c:consinit(),
which resulted in ddb not working on the keyboard/display.
Here is the fix:

*** zs.c.~12~	Fri Oct 17 20:00:42 1997
--- zs.c	Wed Oct 22 10:33:19 1997
***************
*** 955,961 ****
  
  	case 0:	/* keyboard/display */
  #if NKBD > 0
! 		zs_unit = 0;
  		channel = 0;
  		cn = &consdev_kd;
  		/* Set cn_dev, cn_pri in kd.c */
--- 955,961 ----
  
  	case 0:	/* keyboard/display */
  #if NKBD > 0
! 		zs_unit = 1;	/* XXX - config info! */
  		channel = 0;
  		cn = &consdev_kd;
  		/* Set cn_dev, cn_pri in kd.c */
***************
*** 970,976 ****
  	case PROMDEV_TTYA:
  	case PROMDEV_TTYB:
  		zstty_unit = inSource - PROMDEV_TTYA;
! 		zs_unit = 0;
  		channel = zstty_unit & 1;
  		cn = &consdev_tty;
  		cn->cn_dev = makedev(zs_major, zstty_unit);
--- 970,976 ----
  	case PROMDEV_TTYA:
  	case PROMDEV_TTYB:
  		zstty_unit = inSource - PROMDEV_TTYA;
! 		zs_unit = 0;	/* XXX - config info! */
  		channel = zstty_unit & 1;
  		cn = &consdev_tty;
  		cn->cn_dev = makedev(zs_major, zstty_unit);