I just bought a brand new iPhone (1.0.2 still - AppleStore San Francisco) and applied AnySIM. At some point during the firmware write, an error occurred: Oops, someting went wrong writing.... From that point Wifi was gone, which indicated to me that the baseband was not written to the phone.

I tried to restore using iTunes, but iTunes too produced an error (1011) and could not write the firmware. Turns out that when I looked for the error, it also occurred with non-hacked iPhones. Fortunately, the AppleStore exchanged my phone, but they could have concluded that I tried to apply the hack (as the phone was activated without an AT&T subscription) and therefore might have refused the exchange (in fact, the Genius figured something was wrong with the replacement phone when it showed 'no service' with the AT&T sim inside - I convinced him to just give the phone and "let me rush to my other appointment" before he would figure it out).

My advice: when possible: try and restore the phone from iTunes _before_ applying the hack, just to make sure this problem is absent before applying the hack, so you can exchange the product if it has the problem.