iPhone 3G w/ 5.15.04 firmware and IOS 4.2.1 at "Insert a valid SIM with no PIN..."

[thehighend]

Hi,
I just bought this used iPhone 3G today and it worked with my own T-Mobile SIM card for a couple of minutes before I let iTunes perform a software update to bring it from IOS 4.0 to IOS 4.2.1. After the update, I am stuck on a boot-up screen that says: "Insert a valid SIM with no PIN lock" and it won't accept my T-Mobile SIM (not surprisingly).

Is there a way to get past this? I read about using the iPad's firmware (6.15.x) on my iPhone 3G, but I'd rather not do that. Is there another option?

 

[Crystal-RX]

Hi,
I just bought this used iPhone 3G today and it worked with my own T-Mobile SIM card for a couple of minutes before I let iTunes perform a software update to bring it from IOS 4.0 to IOS 4.2.1. After the update, I am stuck on a boot-up screen that says: "Insert a valid SIM with no PIN lock" and it won't accept my T-Mobile SIM (not surprisingly).

Is there a way to get past this? I read about using the iPad's firmware (6.15.x) on my iPhone 3G, but I'd rather not do that. Is there another option?

Because you hit the update in Itunes, IOS has updated to 4.2.1 as well as baseband to 05.16. Ultrasn0w does not work with this baseband. So, if you want to unlock again to use with your T-Mobile sim, you will have to install an Ipad baseband.

Here is what you need to do;

1. download Ipad firmware 3.2.2 to your machine.
2. download 3G 4.2.1 firmware to your machince.
3. download redsn0w 0.9.6b6 to your machine.
4. Run redsn0w, once it asks for firmware, point to the 4.2.1 you download to your machine.
5. click install Cydia & ipad baseband, then next, then following redsn0w instruction.
6. Once it is jailbreak, Cydia icon will be appear on your home screen.
7. Open Cydia, then install Ultrasn0w from cydia to unlock your phone.