Here is the last official Phase 5 released firmware, before DCE started writing firmware with Grex support instead of Bvision:
edit: link removed by x56h34
So far none of the Phase 5 support sites seem to have it, and are using the slightly older version.
blizzppc.device will be V44.33 after this update
cybppc.device will be V44.69 after this update
This is the firmware to use, as it's the latest one with BVision support in it, otherwise for Grex support obviously the newer one should be used.