update cpu microcode for old socket a m7mia motherboard (amd761/via686B chipset)?

[stanwebber]

the reason for holding onto this motherboard is that it's the last socket a board to have an isa slot which is useful for soundcard compatibility in old dos gaming. the last bios update MIA1101B/F.BIN (http://www.biostar-usa.com/mbdownloads.asp?model=M7MIA) only includes cpu support for up to an athlon xp 2100+ (palomino). i know it's possible to run the later barton core athlons cpus on this board, but obviously they're not recognized properly and the advanced instruction sets aren't being utilized by the OS.

i've read thru other posts where the ncpucode.bin microcode was successfully extracted and incorporated from a newer donor bios with a similar chipset. the problem with this board as i see it is the one-off amd761 northbridge / via686b southbridge combination that wasn't widely used (before quickly being replaced with ddr capable via northbridges). what would be an appropriate donor bios to pull the ncpucode.bin from? does matching the chipset for a old socket a bios even matter? the last via chipset developed for the socket a platform was the kt880--would something like the abit kw7-g bios be an appropriate donor.

can someone please give me some direction on where to proceed with this? or if my request is trivial enough just go ahead and patch the m7mia bios with the updated cpu microcode? thanks