After many hours of effort, I finally managed to get my iPhone 3GS SIM unlocked so that I could use it in Europe with a Lebara SIM. I am not reporting the detailed instructions here because there are so many good descriptions already on the web. I just want to report the overall experience in the hope that it might save someone else the trouble that I had.

I could not get redsn0w to work. I tried many different versions but it kept telling me that it could not find the device (even though iTunes was able to see it). I think that the problem had something to do with Mobiledevice.dll. It didn’t recognize it even though I copied it over from C:\Program Files (x86)\Common Files\Apple\Mobile Device Support (on Windows 7) after installing the latest version of iTunes (10.6.1.7). In addition, I downloaded several (3?, 4?) versions from the web while trying to get it to work but never really had any success. In some cases it seemed to work but then it would hang or simply die. It would probably help if the developers told us which version worked best with and where to get it.

I found the error message telling me that I didn’t understand how to put the phone in DFU mode very annoying. Not only was it in DFU mode but iTunes was able to recognize it. It would be helpful if it gave more information that I could use to debug the problem like “can’t find device from such and such DLL function” or “please download <this> version of mobiledevice.dll”. Not all users of redsn0w are so inexperienced that they do not understand how to put an iPhone into DFU mode.

I could not get iOS 5.1 to work either untethered or tethered. The biggest problem was an error code 1600. I could not figure out how to work around it.

The key for me was installing the latest version of iTunes and using sn0wbreeze v2.9.3. I first had to downgrade my iPhone to iOS 5.0.1 (9A405) and install modem firmware version 06.15.00. Beware that you must have the old PROM which you can find if your serial number is older than **135 (35th week in 2011 or so). Mine was **928 (28th week in 2009).

I used the pre-defined downloads available through sn0wbreeze to get the 5.0.1 ipsw file I needed (iPhone2,1_5.0.1_9A405_Restore.ipsw). For the record, I tried 5.1 and various 4.x versions before I found that 5.0.1 worked.

I had to reboot to get it to recognize the cellular network. When I did it said “vodafone” instead of Lebara which is apparently ok.

After completing the unlock, GPS worked just fine for me although some folks have reported having problems.

Here are a few other tidbits: to get your number phone “*#100#”. To get your remaining minutes call 5588.

I must say that it was worth it! Once I got it working it was very cool to be able to use by iPhone rather than the Samsung E1080i that I bought for £5.

It was also nice to avoid paying $0.99 (or $1.29) a minute to AT&T for international roaming charges while having access to cellular networks. If they only charged something reasonable like $0.10 (or even $0.20) I wouldn’t have bothered.

Enjoy!