November 4th, 2006, 12:49
On some PPC models, the 4.0 ISO has been having an issue. This particular issue consists of the kernel panicing on one of the ATA drivers.

wdc1 at kauaiata0 IRQ 39: DMA
panic: trap type 200 at 102ce0 (0+0x102ce0) lr 102ce0
stopped at 0x2655c4: lwz r0,20(r1)

On installing OpenBSD on a PowerPC system, it may be a better idea to install from a HFS partition. You can do so by placing the ofwboot and bsd.rd files in the root of your OS X partition, or an HFS partition, and boot from the OpenFirmware.

After a reboot, after the mac startup chime, press and hold Control-Option-O-F, and wait for the Open Firmware prompt. At the prompt type:

boot hd:,ofwboot bsd.rd

After that, you can continue to install OpenBSD as you please, without kernel panics.