Well if your BlizzardPPC is anything like mine, it may occasionally 'forget' the rather important startup code and settings in its flashrom.
When this happens for me, the ppc, memory, scsi and gfx card just bomb out. However, the 680x0 side still operates (albeit like a snail without the old fast ram). The machine just gets stuck in a crash loop when the startup sequence starts doing stuff without all the hardware initialised.
Try booting without a startup sequence and see if the card is listed in the expansion list.
If it isnt, but you can boot to a shell ok, you should find you have your 680x0 and thats it. Failing all else, I usually reflash at this point and everything works.
Other BPPC hints
1) Once a month *at least*, clean out all the crud that builds up under the heatsink. The thing is a dust trap. Get a tube of good thermal paste for putting the thing back on with (a *small* dollop on the PPC die, having cleaned the cooler underside completely).
2) Install a heatsink on the permedia2 chip. It knows how to get hot :-)
3) If you are powering your 1200T motherboard via the original power connector only, consider adding a 2nd power feed via the original floppy power header. The BlizzardPPC+BVision+Big wedge of RAM tends to draw a lot of current. I have the 040 version which is even more of a hog, and my system is unreliable without this extra feed.
If you use some sort of powered busboard that feeds the whole system, like a mediator, you might not want to do this, or seek advice first.