Apple ipod

iPhone 3G Ver. 3.1.3, UNLOCK for the Tmobile Network?

I have the iPhone 3G and it’s been updated to the latest version I take it. Version 3.1.3… Can anyone give me the step by step guide on how to downgrade or whatever the hell they call it to get the phone to use my Tmobile SIM card with the proper bands needed to connect to the network? I really appreciate any help with this issue! Thanks again.

Only some models can be downgraded..
You can check to see if it can be downgraded by going here: http://ih8sn0w.com/index.php/welcome.snow
and download forcast on the left and open it with your iPhone pluged in. It will tell you if it can be unlocked.. Then if it can be unlocked follow the guide below…

1: First off jailbreak your iPhone, guide here:

http://www.redmondpie.com/jailbreak-iphone-os-3.1.3-firmware-with-redsn0w-0.9.4/

2: Then go to cydia and search for fuzzyband and install it.

3: Then open fuzzyband and flash the phone.. (Its really easy just hit downgrade)

4: After you do that download the correct 3.1.2 firmware here: http://www.felixbruns.de/iPod/firmware/

5: Then plug the iPhone into iTunes and downgrade the firmware by holding shift key and then click restore or if your on a mac hold option key then click restore.. It will let you select the 3.1.2 firmware you downloaded in step 4. Then the iphone will downgrade to 3.1.2

6: Now go to http://blackra1n.com/ and click on ether windows or mac icon and download blackra1n then click make it ra1n. The phone will reboot.

7: Now that the phone is jailbroken click on the blackra1n icon (on the iPhone) and there will be an option to install black weather.. click it and it will install..

Your iphone will now be jailbroken and unlocked

yellowsn0w Unlocked iPhone 3G On T-Mobile US Firmware 2.2 Baseband 02.28.00