Well, I've been trying to get a -current built with some (but not all) of 
the MacROM debugging code turned on.  Turns out that the macrom.c code 
has a minor problem in that it attempts to call tron() and troff() in the 
initialization code, even if support for tracing has not been selected 
via MRG_TRACE.  The following patch will fix this:

--- macrom.c.orig	Sun Mar 26 08:10:12 1995
+++ macrom.c	Sun Mar 26 08:12:47 1995
@@ -588,16 +588,20 @@
 	printf("\n");
 
 	printf("Turning on a trace\n");
+#if defined(MRG_TRACE)
 	tron();
+#endif
 	printf("We are now tracing\n");
+#if defined(MRG_TRACE)
 	troff();
+#endif
 	printf("Turning off trace\n");
 	dumptrace();
 
 	for(i = 0; i < 500000; i++)
 		if((i % 100000) == 0)printf(".");
 	printf("\n");
-#endif
+#endif	/* MRG_TEST */
 
 #if defined(MRG_DEBUG)
 	printf("after setting jump points\n");


Now maybe I can put some time into figuring out why the macrom code 
doesn't work on my Mac IIci.