Well I don't have the 890GX board in use right now (was actually /trying/ to sell it), since I got this 890FX heh
All the info I have can be found in this single thread :) Started out with modding it before I had the board even, but then I updated it once I managed to find it.
http://techpowerup.com/forums/showthread.php?t=116661
I've been through Rebel's Haven a number of times though, just not much recently is all. Couldn't find anything of help. The forums don't have new registration opened, so I emailed Polygon (I think that's his name), asking if he knew anything or could do a CRC check. He just said no and only Gigabyte could. So I left it at that >_>
I was successful in modding Award/Award-Phoenix BIOSes with MODBIN up to S939 though :\ If I manage to get this CPU I'm hoping to, I'll have enough spare parts to build the 890GX again, so I might try with MODBIN 2.04.03 that I came across recently (it's on RH actually I think).