Gigabyte MA770-UD3 Rev 2.0 ACC Boot Bug Issue (Fixed BIOS?)

[RSX]

Hi,
I have a weird problem with my Gigabyte MA770-UD3 Rev 2.0 and an AMD Athlon X2 5000+ 45nm (Deneb Core). If I set "EC Firmware" to "Hybrid" and ACC to "Auto/All Cores/Per Core" a Phenom FX-5000 quad core processor shows up. CPU Core Control is set to auto. It is completely stable @ 1,375 V with it's additonal cores and L3-Cache. Tested it with a prime95 custom test for about 10 hours. So far so good. But if I shut down the system for a few seconds or more, ACC resets to default -> disabled. The rest of my configurations like voltages remained like I set them before. So, only the dual core cpu shows up again. Then I activated ACC again, but set "CPU Core Control" in the same menu of the BIOS to "manual". The quad core was active again. I shut down the system again for a few minutes to test if the problem is fixed. Well, as you can imagine another problem occured.

If I press the start-button, all fans start their work, the HDD doesn't make any sound -> it's not running yet, and shuts itself down after ~5 seconds. Any attempt to start the PC fails at this moment. I have to switch the PSU off for about 10 seconds and try it again. This happens 2 to 5 times in a row til the HDD boots and I get to see the regular BIOS image. Everything boots fine. 4 Cores and the extra L3-Cache show up. Now this is a very annoying problem.

I've increased all kinds of voltages, tried different PSUs, RAM, BIOS versions. And nothing helped.

This is my second Thread today. Please excuse me. I don't know where this thread fits best.

So, is it possible to fix the problem by a custom/modded BIOS?

Thanks!

Greets