Whomever is claiming that sun4c-only kernels don't work is seemingly
off their rocker:

NetBSD lestat 1.4G NetBSD 1.4G (LESTAT) #161: Tue Jul 20 13:01:24 PDT 1999 \
  thorpej@lestat:/amd/dracul/u2/netbsd/src/sys/arch/sparc/compile/LESTAT sparc

That is a sun4c-only kernel, running on my SS2:

NetBSD 1.4G (LESTAT) #161: Tue Jul 20 13:01:24 PDT 1999
    thorpej@lestat:/amd/dracul/u2/netbsd/src/sys/arch/sparc/compile/LESTAT
total memory = 32672 KB
avail memory = 29728 KB
using 128 buffers containing 512 KB of memory
bootpath: /sbus0/esp@0,800000/sd@1,0
mainbus0 (root): SUNW,Sun 4/75
cpu0 at mainbus0: cache chip bug; trap page uncached: CY7C601 @ 40 MHz, TMS390C6
02A FPU
cpu0: 64K byte write-through, 32 bytes/line, hw flush: cache enabled
memreg0 at mainbus0 ioaddr 0xf4000000
clock0 at mainbus0 ioaddr 0xf2000000: mk48t02 (eeprom)
timer0 at mainbus0 ioaddr 0xf3000000 ipl 10 delay constant 18
auxreg0 at mainbus0 ioaddr 0xf7400003
zs0 at mainbus0 ioaddr 0xf1000000 ipl 12 softpri 6
zstty0 at zs0 channel 0
zstty1 at zs0 channel 1
zs1 at mainbus0 ioaddr 0xf0000000 ipl 12 softpri 6
kbd0 at zs1 channel 0 (console)
ms0 at zs1 channel 1
audioamd0 at mainbus0 ioaddr 0xf7201000 ipl 13 softpri 4
audio0 at audioamd0: full duplex
sbus0 at mainbus0 ioaddr 0xf8000000: clock = 20 MHz
dma0 at sbus0 slot 0 offset 0x400000: rev 1+
esp0 at sbus0 slot 0 offset 0x800000 level 3: ESP100A, 20MHz, SCSI ID 7
scsibus0 at esp0: 8 targets, 8 luns per target
probe(esp0:1:0): max sync rate 4.03Mb/s
sd0 at scsibus0 targ 1 lun 0: <SEAGATE, ST1480   SUN0424, 6266> SCSI2 0/direct f
ixed
sd0: 411 MB, 1476 cyl, 9 head, 63 sec, 512 bytes/sect x 843284 sectors
probe(esp0:2:0): max sync rate 4.03Mb/s
sd1 at scsibus0 targ 2 lun 0: <SEAGATE, ST34371N, 0484> SCSI2 0/direct fixed
sd1: 4148 MB, 5172 cyl, 10 head, 164 sec, 512 bytes/sect x 8496884 sectors
probe(esp0:3:0): max sync rate 4.03Mb/s
sd2 at scsibus0 targ 3 lun 0: <SEAGATE, ST1480   SUN0424, 6266> SCSI2 0/direct f
ixed
sd2: 411 MB, 1476 cyl, 9 head, 63 sec, 512 bytes/sect x 843284 sectors
cd0 at scsibus0 targ 6 lun 0: <SONY, CD-ROM CDU-8012, 3.1e> SCSI2 5/cdrom remova
ble
le0 at sbus0 slot 0 offset 0xc00000 level 5: address 08:00:20:11:2d:46
le0: 8 receive buffers, 2 transmit buffers
cgsix0 at sbus0 slot 3 offset 0x0 level 7: SUNW,501-1672, 1152 x 900, rev 6 (con
sole)
cgsix0: attached to /dev/fb
fdc0 at mainbus0 ioaddr 0xf7200000 ipl 11 softpri 4: chip 82072
fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec
root on sd0a dumps on sd0b
root file system type: ffs

...just wanted to provide my input :-)

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>