Guys* I am facing the same problem as the author of this topic. I had 4.1 firmware on my 3GS with some unlockable baseband* which I dont remember. I used redsn0w 0.9.6b6 and tried to install Cydia and 06.15.00 baseband* but the phone was stuck on Flashing baseband (dont interrupt). After staying in that condition for about 5-10 minutes the phone restarted and Apple logo showed up.
I dont have my SHSHs blobs saved so cant go back to 4.1. I know I f*cked up* but I really need your help guys. Any suggestions?