Technical questions about T-Mobile iPhone 5

[BiggAW]

I can't seem to get to the bottom of the news about the T-Mobile update for unlocked iPhones or the lack of Band IV UMTS support for existing iPhones.

For the T-Mobile software update, what did they actually enable? I keep seeing references to LTE, but the unlocked iPhone already supported LTE on four bands, including Bands IV and XVII, in addition to II and V. Is it some carrier setting specific to T-Mobile? Or auto-configuration of something?

Also, why can't the existing iPhones that are unlocked or on AT&T be "re-flasked" so to speak to work on UMTS Band IV? They have UMTS hardware, and they have Band IV hardware, so what is stopping them from getting UMTS Band IV running? The chips seems to support everything under the sun, it's just a matter of amps and antennas, and the iPhone 5 obviously has those working on Band IV for LTE.

Everyone seems so confused about these things.

 

[bozzykid]

Unlocked phones without carrier support do have a LTE toggle switch. Apple is sending out a carrier update to T-mobile users that will provide the correct APN settings (so you probably can't change APN settings manually anymore) and enable Visual Voicemail. The carrier update will also enable the LTE toggle so LTE can be utilized.

As for the hardware, apparently Apple didn't enable the AWS band in the firmware and that part of the firmware can't be enabled with a software update. So a software update is not possible. It really makes no sense why they would have it disabled but they choose to do it (probably to keep AT&T happy).

 

[BiggAW]

So you couldn't get to the setting to turn the LTE on? That's brilliant.

Wow, it sounds like they purposely blocked it out at low level to make AT&T happy, and now they have made a mess with it.

 

[bozzykid]

So you couldn't get to the setting to turn the LTE on? That's brilliant.

It is because Apple will not allow LTE on any network without testing. There are backdoors to enable it (especially if you are jailbroken). But in general, Apple has to approve of the network before the LTE option is available.

 

[BiggAW]

It is because Apple will not allow LTE on any network without testing. There are backdoors to enable it (especially if you are jailbroken). But in general, Apple has to approve of the network before the LTE option is available.

Ah, gotcha. So nothing to do with LTE on Band IV, and everything to do with LTE on T-Mobile.