Jailbroken American Iphone4 not working with Dutch Telfort SIM

[RabbleRebel]

Hi all! I really dig the forum and the help you provide.
So a friend of mine recently visited from the Netherlands and bought an iPhone4 here in the US. I Unlocked and Jailbroke it with the GreenPoison hack and I verified that it worked - I used a cut Verizon SIM card to make a few calls - all of which connected.

Since going back to the Netherlands, though, he put in a Dutch Telfort SIM card and now the iPhone won't work as a phone - there's never signal and he can't call out. Does anyone know what the problem is, if Dutch Telfort SIM - or European SIMs in general won't work with an American Iphone4?

Thanks!

Other info:
4.1 OS 8B117
Modem Firmware - Baseband 02.10.04
Hacked with GreenPoison

[Simon]

US iPhones are locked to ATT. There is no unlock yet for that baseband.

[RabbleRebel]

US iPhones are locked to ATT. There is no unlock yet for that baseband.

Thanks for the reply!

But, if that's the case, why was I able to make a call with the Verizon SIM?

[Simon]

Are you sure it was a verizon sim and not a ATT sim? The regular GSM iPhone cannot run on verizon even if it was unlocked.