How to get FaceTime to work on T-Mobile USA on 4.1.

[Numbski]

For the moment, MiTime is incompatible with 4.1. @pushfix on Twitter has dropped off of the face of the planet for the moment, so don't expect this to change or be fixed any time soon. If you have a phone and don't have your SHSH stored for 4.0.2 or prvious, you're SOL. I'm sorry, that's just all there is to it. @pushfix was trying to get email activation working for FaceTime on the iPhone 4, but apparently failed. I'll look into this further myself if I have time, but in short there's an activation token that is signed by the carriers during the activation process, much akin to push messages having a signed token and youtube having one. This all happens when you activate your phone, EXCEPT FaceTime. You get that via a special sms/mms upon first use.

So the "fix" is to get a sim card from a valid carrier.

WARNING:
The following will get you working, however there is a degree of risk as you will not be able to use PwnageTool to prevent your baseband from getting updated. Currently, there is no way to carrier unlock a baseband newer than 1.59.00, which you can check using Settings->General->About->Modem Firmware. You will have to rely on TinyUmbrella to prevent this from being updated, and by doing so you expose yourself to the risk of a newer baseband update being flashed to your phone and removing the ability for you to carrier unlock with Ultrasn0w. This is avoided when you use PwnageTool because the baseband firmware put into your custom ipsw will be 1.59.00, thus keeping you safe. YOU WILL NOT BE PROTECTED IF YOU DO THIS INCORRECTLY! You've been warned!

If you're in the USA, just spring for a GoPhone sim from AT&T. It will cost your $15, but you'll be able to use it forever more or less. Remove all sim cards, wipe and restore your phone back to 4.0, 4.0.1, or 4.0.2 while running TinyUmbrella. DO NOT JAILBREAK. DO NOT USE PwnageTool (sadly). TinyUmbrella will prevent a baseband update from happening, and the restore will appear to fail with an error code. Power off the phone, power it back on. It will bring you to a "plug into iTunes" screen. Plug it in, and within PwnageTool use the "kick out of restore mode" function. You will now get a more normal boot.

This will bring your phone to the state where it will want to activate. Insert your AT&T (or other valid carrier, NOT a phonebook sim) sim card, and plug the phone into iTunes. This will legitimately activate the phone and set lockdownd to state "WildcardActivated". Hacktivation sets it to "FactoryActivated" which will not work.

Now, jailbreak the phone using GreenPois0n, install cydia, and from cydia install Ultrasn0w. Remove the AT&T sim, reboot, put the T-Mobile sim in and verify that you have service. Note: Ultrasn0w seems to be flaky on 4.x. Sometimes the unlock fails at boot time. DON'T PANIC. Just reboot your phone again. Will usually succeed. Don't put your phone back into it's case if you have one. Go back into Cydia and install MiTime. Run MiTime, it may tell you to remove your sim card and plug it back in. COMPLY WITH THIS. Carrier bundles get mis-associated in this process, and you definitely want the correct carrier bundle assigned prior to attempting FaceTime activation.

Once you have MiTime set up and all settings are good, feel free to test FaceTime out. Once you do that...

Plug your phone into the computer, and back it up using iTunes. Turn your phone off, remove the T-Mobile SIM card, leaving no sim card inserted. Wipe and restore to 4.1 while running TinyUmbrella, DO NOT JAILBREAK. DO NOT USE PWNAGETOOL. Again, baseband update will be prevented, but iTunes restore will claim to "fail". Use TinyUmbrella to kick out of restore mode. Get to the point where it wants to be plugged into iTunes to activate. Insert your valid AT&T sim, Activate and get to the springboard - again, at this point your lockdownd should be "WildcardActivated". iTunes will ask if you want to restore from backup. Say yes, and choose the backup you just made. NOW YOU CAN JAILBREAK. Install Cydia, install Ultrasn0w, shut off your phone, swap to your T-Mobile sim card, boot up, verify you have service. FaceTime will still not work at this point. Go into Cydia and install MiTime. The latest version of MiTime will restore your previously activated FaceTime token. *Now* FaceTime will work for you on 4.1.

Ongoing, until MiTime is made to work with later iOS versions, you will have to restore your phone from a backup where FaceTime was already working. If FaceTime has never worked for you before, you *must* restore to 4.0, 4.0.1, or 4.0.2, and you must *always* activate with a legitimate carrier sim to put lockdownd in state "WildcardActivated". If you want to know what state your phone is currently in, ssh into your phone and do this:

grep determine_activation_state /var/logs/lockdownd.log

There's no typo there, it really is "/var/logs", not "/var/log".

If you're doing it right, you'll get something like this:

Fri Dec 24 14:14:55 2010 pid=36 (0x3e088868) determine_activation_state: SIM status: kCTSIMSupportSIMStatusReady
Fri Dec 24 14:14:55 2010 pid=36 (0x3e088868) determine_activation_state: No ICCID in the activation record
Fri Dec 24 14:14:55 2010 pid=36 (0x3e088868) determine_activation_state: The record contains a wildcard ticket
Fri Dec 24 14:14:55 2010 pid=36 (0x3e088868) determine_activation_state: The activation state has not changed.
Fri Dec 24 14:34:11 2010 pid=36 (0x3e088868) determine_activation_state: This device is a phone. It supports factory activation.
Fri Dec 24 14:34:11 2010 pid=36 (0x3e088868) determine_activation_state: The original activation state is WildcardActivated

If it says "FactoryActivated", return to square one. Cleanly wiped phone, DO NOT restore from any backup. Activate with legitimate sim, jailbreak, ssh in, check this again. YOU MUST BE WildcardActivated! ALWAYS!

[babyblue_pimp]

You can use pwnagetools, just make a bundle where it doesn't automatically activate the phone (requires ATT sim)

Downgrade to 4.0.2 or lower with pwnage and using att sim, use MiTime to activate Facetime, then simply update to 4.1 using pwnagetools, again disabling hacktivation, and using the ATT sim to activate. Your Facetime will still be active. This has worked for many iPhone's that i've done.

I've also had FaceTime automatically activate after a little while on a few T-Mobile iP4's, but none had a solid method to follow, just happened after a while on wifi.

Either way, not trying to bash your method, there are plenty of people on here having problems with Facetime, hopefully your method works for people!

[Numbski]

No, I appreciate you pointing out that you can create an PwnageTool ipsw that doesn't hacktivate. The key is making sure that you're WildcardActivated.