iPhone Unlocking iPhone 4/4S for T-Mobile

[mohsy90]

Alright I'm trying to help a friend out whose looking to switch to t-mobile. I suggested he purchase a factory unlocked iPhone 4S instead of buying a jailbroken iPhone 4 that is unlocked using ultrasnow or a gevey sim.

Well, I've been searching around and noticed individuals that are buying used at&t iPhone 4/4S and buying At&t sanctioned unlocks from websites or other forum members on marketplace forum. Can anyone enlighten me on exactly how this process works and any important notes I should know when buying a used iPhone 4/4S. I've been hearing that if you buy an iPhone 4/4S thats attached to an at&t contact the unlock won't work, is this true?

Only reason I ask is that going through the at&t route seems to be considerably cheaper than purchasing a factory unlocked iPhone.

 

[dhlizard]

For iPhone4 unlocks, here are the options depending on baseband:
Software unlock Ultrasn0w: bb 1.59.xx only
Hardware unlock Gevey sim interposer: bb up to and including 4.10.xx
IMEI unlock from carrier who sold the phone: all bbs

For iPhone4S unlock, Gevey Ultra 4S for all basebands
IMEI unlock from carrier who sold the phone: all bbs

And the baseband cannot be changed or downgraded

Next time, provide the basebands. Unlocks are baseband dependent !

 

[mohsy90]

For iPhone4 unlocks, here are the options depending on baseband:
Software unlock Ultrasn0w: bb 1.59.xx only
Hardware unlock Gevey sim interposer: bb up to and including 4.10.xx
IMEI unlock from carrier who sold the phone: all bbs

For iPhone4S unlock, Gevey Ultra 4S for all basebands
IMEI unlock from carrier who sold the phone: all bbs

And the baseband cannot be changed or downgraded

Next time, provide the basebands. Unlocks are baseband dependent !

I understand the ultraslow and gevey sim unlocks, but how do the IMEI unlocks work. Can you buy any used at&t iPhone and purchase an unlock from a website or another member that has them available? I've heard that if someone sells an iPhone that is attached to a contract the unlock won't work. Can anyone confirm this.

Also, is this only for iPhone 4S or does it work with iPhone 4.

 

[dhlizard]

IMEI unlocks are generally done by carrier who sold phone

 

[labman]

IMEI unlocks offered by anything other then the carriers are grey market and exactly that lots of people are happy but it's still a grey area market. you pay for the service and hope for the best.