NetBSD/macppc 8.0 has a bug that boot floppies don't boot
https://gnats.netbsd.org/53727
and it should be fixed in 8.1_RC1:
https://cdn.netbsd.org/pub/NetBSD/NetBSD-8.1_RC1/macppc/
Indeed the bug fix worked. I was able to use 8.1 RC1 floppies to install from my 8.0 CD, and I now have a bootable system. dmesg:
--
NetBSD 8.0 (PERFORMA6400) #1: Sat May 25 15:25:25 EDT 2019
root@:/usr/src/sys/arch/macppc/compile/PERFORMA6400
total memory = 49152 KB
avail memory = 41212 KB
timecounter: Timecounters tick every 10.000 msec
found ohare PIC at f3000000
bootpath: ata/ATA-Disk@0/netbsd
mainbus0 (root)
cpu0 at mainbus0: 603ev (Revision 2.1), ID 0 (primary)
cpu0: HID0 0x90c001<DOZE,DPM,ICE,DCE,NOPTI>, powersave: 1
cpu0: ohare L2 cache enabled
memory0 at mainbus0
bandit0 at mainbus0
pci0 at bandit0 bus 0
pci0: i/o space, memory space enabled
pchb0 at pci0 dev 11 function 0
pchb0: Apple Computer Bandit Host-PCI Bridge (rev. 0x03)
obio0 at pci0 dev 16 function 0: addr 0xf3000000
mesh0 at obio0 offset 0x10000 irq 12: 50MHz, SCSI ID 7
scsibus0 at mesh0: 8 targets, 8 luns per target
zsc0 at obio0 irq 15,16
zstty0 at zsc0 channel 0 (console i/o)
zstty1 at zsc0 channel 1
awacs0 at obio0 offset 0x14000: irq 17,8,9
awacs0: speaker
audio0 at awacs0: full duplex, playback, capture, mmap
awacs0: Virtual format configured - Format SLINEAR, precision 16, channels 2, frequency 44100
awacs0: Latency: 278 milliseconds
swim3 at obio0 offset 0x15000 not configured
nvram0 at obio0 offset 0x60000
cuda0 at obio0 offset 0x16000 irq 18
nadb0 at cuda0: Apple Desktop Bus
iic0 at cuda0: I2C bus
wdc0 at obio0 offset 0x20000 irq property not found; using 13: DMA transfer
atabus0 at wdc0 channel 0
tlp0 at pci0 dev 17 function 0: DECchip 21041 Ethernet, pass 1.1
tlp0: interrupting at irq 22
tlp0: Ethernet address 00:a0:40:5c:b3:7c
tlp0: 10baseT, 10base2, 10base5
vmmask 79c00000 schedmask 7fc00000 highmask 7fc00000
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0
timecounter: Timecounter "mftb" frequency 10000000 Hz quality 100
scsibus0: waiting 2 seconds for devices to settle...
adbkbd0 at nadb0 addr 2: extended keyboard
adbkbd0: extended protocol enabled
wskbd0 at adbkbd0 mux 1
wsmouse0 at adbkbd0 mux 0
adbms0 at nadb0 addr 3: EMP mouse <@200> 1-button, 200 dpi
wsmouse1 at adbms0 mux 0
cd0 at scsibus0 target 0 lun 0: <DEC, RRD42 (C) DEC, 1.4a> cdrom removable
cd1 at scsibus0 target 3 lun 0: <MATSHITA, CD-ROM CR-8008, 8.0e> cdrom removable
wd0 at atabus0 drive 0
wd0: <QUANTUM FIREBALL_TM1700A>
wd0: drive supports 16-sector PIO transfers, LBA addressing
wd0: 1628 MB, 3309 cyl, 16 head, 63 sec, 512 bytes/sect x 3335472 sectors
wd0: drive supports PIO mode 4, DMA mode 2
wd0(wdc0:0:0): using PIO mode 4, DMA mode 2 (using DMA)
swwdog0: software watchdog initialized
--
Everything appears to be functional. Thanks as always to the list for pointing me in the right direction.
-Henry