I have received a lot of messages regarding this issue. For some of us this could seem just obvious but apparently it isn't...
Hre is what has worked for me:
Situation: Many early iPhones unlocked with anysim (and the like) got damaged during 'updates" and now have the 0049 IMEI issue and/or cannot update/unlock/get signal etc...
Solution: (not in details but EASY enough to implement)
1. Restore using iTunes to 1.1.1 (if you just can't, then 1.0.2 and back to 1.1.1)
2. Jailbreak and virginize baseband
3. Restore again using iTunes to 1.1.1 (might need to do it twice and boot with ibrickr)
4. Manually put in restore mode and reconnect to iTunes
5. Restore and update to 1.1.4 (Should be successfull at first attempt)
6. With ZiPhone 2.5c "DO IT ALL"
Phone will reboot to a clean and 100% functional 1.1.4 (itunes - LocateMe - youTube) and with new modem FW.
Good Luck and I hope this was somewhat useful.