>On the other hand, if I boot off the MacOS IDE drive, everything
>probes fine, but when /etc/rc gets to initializing bm0, the machine
>hangs. Debugging printfs show bmac_init looping forever on the "Wait
>for reset completion" line.

Perhaps this patch will work.

*** sys/arch/macppc/dev/if_bm.c	Fri Jan  1 10:27:52 1999
--- sys/arch/macppc/dev/if_bm.c	Sat Apr 24 16:08:27 1999
***************
*** 174,181 ****
  	int i;
  
  	sc->sc_flags =0;
! 	if (strcmp(ca->ca_name, "ethernet") == 0)
  		sc->sc_flags |= BMAC_BMACPLUS;
  
  	ca->ca_reg[0] += ca->ca_baseaddr;
  	ca->ca_reg[2] += ca->ca_baseaddr;
--- 174,187 ----
  	int i;
  
  	sc->sc_flags =0;
! 	if (strcmp(ca->ca_name, "ethernet") == 0) {
! 		char name[64];
! 
! 		bzero(name, 64);
! 		OF_package_to_path(ca->ca_node, name, sizeof(name));
! 		OF_open(name);
  		sc->sc_flags |= BMAC_BMACPLUS;
+ 	}
  
  	ca->ca_reg[0] += ca->ca_baseaddr;
  	ca->ca_reg[2] += ca->ca_baseaddr;