Athlon II 445 x3 wont unlock after bios update

This happened a couple months ago, at first I didnt mind whatever, but now its starting to bother me. So I had my cpu unlocked tp a phenom ii b45 x4 for a good few months (and I had spent the first month rigorously stress testing it with prime 95 and other programs, it worked perfectly ). I have a hyper 212+ cooler so cooling doesnt seem to be the issue (atm it run runs my athlon x3 at 3.7ghz 1.4v at max load temps of 40-43'C). How ever I updated my bios and flashed it to the lastest version and the core unlock wont even give me a option to turn the 4 core on or off, it's like its invisible. I looked at what the bios update did and all it did was increase memory compatability and the agesa code. So im guessing amd didnt like ppl unlocking their athlons and updated the agesa code to make it so the 4 core doesnt even show up under bios. Ive tried flashing my mobo multiple times to newer versions to no chance. I am using a msi 870-g45 motherboard (770 chipset board). Would flashing my mobo back to earlier version fix this? and how can I flash bk to a earlier version? and which version do I flash bk to? I dont remember what version I had before it stopped working.
Thanks for any feedback!