iOS 5 Blocks Gevey Sim Unlock From Working – Downgrade To Older Base Band / Modem Firmware

Gevey Sim ehhh? You what?

A lot of people in the UK have never heard of a Gevey Sim before and do not know what it does.

A Gevey Sim unlocks all networks on your iPhone without jailbreaking or when the ultrasn0w jailbreak doesn’t work because of your iPhone’s ‘baseband’. It’s a special sim card tray with a chip that bypasses the iPhone’s network lock via the emergency calls function of the phone.

iOS 5 Blocks Gevey Sim From Unlocking Networks

Yesterday I was one of the many who fell into the trap of upgrading to iOS 5 after seeing all the good new features but not realising my Gevey Sim wouldn’t work anymore.

The new iOS 5 stops the Gevey Sim from bypassing calls through the emergency call function by updating the baseband (BB) – you will find it on your phone called ‘Modem Firmware’ under Settings -> General -> About.

I ended up with the BB (baseband) 04.11.08 which is NOT COMPATIBLE with the Gevey Sim. (As of 16th Oct’ 2011)

How to Downgrade iOS5 to Baseband 04.11.08 to 04.10.01 (iOS 4.3.5 Baseband)

*IMPORTANT! READ THIS FIRST!

This will only work while Apple is still ‘signing’ the 4.3.5 firmware with the Gevey compatible baseband. When more people convert to iOS5 – Apple will stop ‘signing’ 4.3.5 and your phone may be stuck forever on its network unless Gevey or someone else produces a new work-around. Which there is no news of as yet…

Step One

Download the iOS4 firmware 4.3.5 for your specific device:

Download iPhone 4 GSM 4.3.5 Firmware

Download iPhone 3GS 4.3.5 Firmware

Step Two

Point your hosts file to Apple.

Do this by downloading TinyUmbrella.

Download TinyUmbrella Windows Version

Download TinyUmbrella OSX Version

Once downloaded open it. When I did it I got these 2 messages – just press OK.

Go to the ‘Advanced’ tab and UNTICK the ‘Set Hosts to Cydia on Exit’ box.

Now exit TinyUmbrella as this is all you use it for this time, easy isn’t it! 😉

Step Three

Connect your iPhone to your computer (turned on or off it doesn’t make a difference) and put your iPhone into DFU mode.

Enter DFU mode by holding the ‘home’ and ‘power’ buttons together for exactly 10 seconds at which point you must release ‘power’ but continue to hold ‘home’. After about 15 seconds, the device will enter DFU mode.

Step Four

Open iTunes – it will know it is in DFU / recovery mode and a message may appear to tell you this. Just press OK (or whatever!).

Now on the main iTunes screen press shift-restore (Windows) or option-restore (OSX), and select the 4.3.5 firmware you downloaded in step 1.

If you followed the above steps correctly (including making sure Apple are still signing 4.3.5 with the 04.10.01 baseband) it should only be a short while until your firmware is downgraded back to 4.3.5 with the Gevey compatible 04.10.01 baseband!

Now you’re phone is safe remember not to use normal iTunes procedures to update your phone if you want to keep using the Gevey Sim (or even ultrasn0w via cydia) to keep all networks unlocked.

So if you’re using a Gevey Sim to network unlock your device DO NOT Update with the normal iOS5. Please read below on how to get around this.

Instead, to continue using your Gevey Sim you will HAVE to update to iOS5 while preserving the precious BB (baseband). Coming soon…

Now if you want to have an untethered jailbreak after doing this you will have to downgrade to 4.3.3 or lower as there is not an untethered jailbreak for 4.3.4 or 4.3.5 – follow the steps here.

Buy a Gevey Sim Now! Click here or the Gevey image below! (Please open tab in new window)

Buy a Gevey Sim Now! Click here or the Gevey image above! (Please open tab in new window)