Phenom 955 not working

I bought a new Phenom II 955 Black Edition for my M2N-SLI deluxe. I installed it to find out the multiplier is stuck at 4x. This is a well known problem (that I didn't know about when I first got it ) and the solution is basically to use N-Tune to set the multiplier to 16-18 (BIOS changes don't work).

The problem I am encountering is that ntune won't let me change the multiplier. I tried to google search it, but all the answers I found are "you should be using the BIOS". Of course, that doesn't work for me in this situation. Any suggestions?