The herolz app worked for me as well.
For those who want to check if their sgs2 is locked: Type *#7465625# in dialer
Sent from my GT-I9100 using XDA App
I have been flashing a lot of ROMs recently, in the hope of finding one with better A2DP Quality, and found out that MoDaCos Custom Rom sounds significantly better. I switched back to Light'ning ROM 6 afterwards, but after flashing MoDaCos liba2dp...