You can use this BIOS. It's just one setting you need to turn off:
Go into BIOS Settings, and disable "OnBoard Sound".
v5pmi.bin is based on the v5Patched BIOS.. which has added support for the new sound chip used on the v5. Historically, the whole purpose of creating v5Patched was to enable Audio on the v5's -- while all other machines would just use the v1 BIOS. Later on, v5Patched just got "adopted" as the new standard BIOS, since it was backwards-compatible and seemed to be better at recognizing some finicky hard-drives.