First discovered by TechCrunch, the simple unlocking procedure is said to work with iPhone 5s purchased from AT&T at full price, with the process being quite simple compared to the carrier's traditional previous method of submitting an online form, sending a fax and waiting up to a week for a restore.
The publication was able to confirm the easy one-step process with AT&T's technical support and successfully unlocked the device in iTunes.
"After restoring the device in iTunes, the user is prompted with the usual unlocking message: 'Congratulations, your iPhone has been unlocked,'" the report said.
From that point, according to TechCrunch's Romain Dillet, all that was needed to gain access to T-Mobile's network was the trimming down of a compatible micro-SIM card to fit in the iPhone 5's nano-SIM tray. The device recognized T-Mobile's signal within seconds, allowing both calls and EDGE data to go through without issue.
AT&T iPhone 5 running on T-Mobile's network after unlock.
Dillet explained that when an iPhone is purchased, the handset's IMEI is added to Apple's database, though it appears subsidized phones hold a different status than those purchased at full price without a contract.
While the publication was able to successfully unlock an iPhone 5 purchased through Apple retail, the procedure could not be confirmed on another pre-ordered unit "even though the device was purchased at full price, it was tied to an existing AT&T account during the pre-order process."
It was previously reported that Verizon's iPhone 5 ships unlocked for GSM networks.