If you’ve jailbroken your iPhone, iPad or iPod Touch using PwnageTool 4.3 for Mac, Sn0wbreeze 2.5 for Windows or Redsn0w 0.9.6rc9 that was released by iPhone Dev Team couple of days back and noticed issues such as single signal bar etc. then iPhone Dev team has announced that a fix is on its way.
MuscleNerd of the iPhone Dev Team revealed this on Twitter:
MuscleNerd: The 4.3.1 issues (signal bars, etc) are fixed http://is.gd/OYktXf but need a few days to test all devices + FW (again: not a new unlock!)
MuscleNerd has also clarified that the unlock for iOS 4.3.1 won’t unlock iPhone 4 basebands – 02.10.04 (bundled with iOS 4.1), 03.10.01 (bundled with iOS 4.2.1), 04.10.01 (bundled with iOS 4.3) or iPhone 3G/iPhone 3GS basebands – 05.14.02 (bundled with iOS 4.1), baseband 05.15.04 (bundled with iOS 4.2.1), baseband 05.16.01 (bundled with iOS 4.3) and baseband 05.16.02 (bundled with iOS 4.3.1). Note: You can find your iPhone’s baseband by going to Settings –> About –> Modem Firmware
Ultrasn0w for iOS 4.3.1 will only support iPhone 4 baseband 01.59.00 and iPhone 3G/3GS basebands 04.26.08, 05.11.07, 05.12.01, 05.13.04 and 06.15.00.
MuscleNerd: It’s probably confusing, so worth repeating: this isn’t a new unlock. It’s a compatibility fix for current unlockers only MuscleNerd: (and for those retaining older baseband for resale value even though they don’t use the unlock themselves)
Even if you don’t care about unlocking, it looks like you’ll have to install the Ultrasn0w for iOS 4.3.1 from Cydia to fix the signal bar issue.