Iphone OTB firmware 1.1.1, Modem firmware 04.01.13_G, Itune 7.5, unlock with Anysim 1.1. Tested with Digi and Maxis.

The phone works normal, only the system SMS unreadable. I tried the "SMS fix" program and the SMS from Maxis is now readable. But the phone became unstable and keep losing signal. In the end there is no signal at all. No incoming and outgoing call available. SMS also dead.

Did some research on Internet, some suspect the modem (baseband) firmware corrupted. So I attempt to restore the iphone. Unfortunately, the restore actually upgraded the iphone to firmware 1.1.2 + 04.02.13_G. I was stuck with 1.1.2 and had done some extensive research on the Internet.

I tried to revert back 1.1.1 and even downgrade the baseband back to 04.01.13_G. But the phone functions never work again.

I tried to upgrade to 1.1.2 + 04.02.13_G, downgrade 1.1.1, unlock with Anysim 1.2.1u, install Oktoprep, upgrade to 1.1.2. But the phone functions still never recover.

I was quite sure it is the modem firmware problem because when a non AT&T sim is inserted, after a while the modem firmware info disappears from "setting-general-about" page.

My question to all the experts here are: -
1. What did I miss?
2. Anyone with similar experience?
3. Did Apple alter my iphone in anyway when I do the upgrade to 1.1.2?

Thank you for reading this, any constructive info is greatly appreciated.