|BIOS upgrades generally come from the Motherboard manaufactures despite what it might say about Phoenix BIOS or or any other BIOS manufature.|
So the first place you need to start looking is compaqs website. Motherboard manufacures take the basic BIOS code from the manufacturer then tweak it to suit their own hardware. Updating with BIOS code meant for a different motherboard will kill it stone dead.
Having said that, why do you feel the need to upgrade the BIOS. Is there a problem that you know a BIOS upgrade will solve? If not, I wouldn't bother. You will achieve very little and run the risk of destroying the motherboard of you get it wrong for no good reason.