If your iPhone 4 is locked at baseband 4.11.08, then this can help you out. The team behind Rebel SIM (R SIM) claims to unlock the iPhone 4 baseband 4.11.08 running on firmware iOS 5 with R SIM IV. R-SIM (Rebel SIM) is a turbo SIM card developed by REBEL Alpha X-SIM and does not require jailbreaking the device to unlock it.
REBEL Alpha X-SIM has earlier released R SIM to unlock iPhone 4S on iOS 5.0.1 and basebands 1.0.14, 1.0.13, 1.0.11, R SIM II for unlocking iPhone 4S iOS 5 and R-SM III to unlock iphone 4S iOS 5.1. But still the baseband 4.11.08 was still locked. Now, R SIM IV will unlock the baseband 4.11.08 on iPhone 4.
Those, who are not aware, R SIM is a SIM interposer like TPSIM and GEVEY SIM, which unlocked your iPhone without cutting the original SIM. You just need to insert your SIM into R-SIM tray and insert it into the handset. Then select your country and carrier and enter 112 mode.
How to Unlock iPhone 5 iOS 5 on baseband 4.11.08
You can get R SIM IV to unlock iPhone 4 is available at EachSupplier for $59 and will be delivered in 10 days. Once you get your SIM interposer, you can follow the steps here to unlock your iPhone 4. R-SIM Card is claimed to work with 3G, EDGE and supports MMS, FaceTime as well. It supports all Network SIM Cards 2G, 3G, WCDMA.
However, until now there has been no unlock method available for 4.11.08 and this is the first method to unlock. We still have not tested this method, please do share your luck with R SIM. For more updates connect to us on Facebook, Twitter, and Google+.