I have successfully unlocked the two extra cores of my AMD Phenom II X2 550BE with the MSI 785GTM-E45 Motherboard with the Official V8.0 Bios (currently the only version available as of 12/3/09). Thanks for this helpful thread, i found the information useful.
EC Firmware: changed to Special
Automatic Clock Calibration: set to Auto
No other changes or adjustments needed. The AMD Phenom II X2 550BE is running at the stock speed of 3.1 (but with all four cores available instead of just 2). Passed my preliminary stress testing with wPrime. Important thing is that this is another motherboard to add to the list. Screenshot attached as requested.
PS: What's the FPO of you CPU?