Despite the README, NetBSD/sun4m does not appear to work on the SparcClassic.
I'm using the SunOS 4.1.3_u1 boot.sun4m, booting off a Mac IIsi running NetBSD,
and it has a serial console. The kernel dies as follows:

pmap_bootstrap: installing kernel page tables...(if this doesn't work, fix pmap_
bootstrap4m in pmap.c)done.

panic: bootstrap: could not get interrupt node from prom
Stopped at	0xf80cb164:	jmpl		[%o7 + 0x8], %g0

 A 'trace' in ddb always stops with panic: kernel fault and is different every time.

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