PwnageTool 5.1.1 allows to create custom firmware and preserve modem version for unlock with ultrasn0w or Gevey. PwnageTool 5.1.1 supports all A4 devices:
iPhone 3GS
iPhone 4
iPad 1
iPod Touch 3G
iPod Touch 4G
Apple TV 2G
You can download RedSn0w 0.9.12b1 here and PwnageTool 5.1.1 here.
Here are our step-by-step tutorials that will guide you through all the process of untether jailbreaking iOS 5.1.1 with absinthe, redsn0wand sn0wbreeze:
Version 0.9.11b4 completes the tethered JB support for 5.1.1 on A4 devices and earlier, including proper “Stitching” and “Custom” creation of NO_BB IPSWs.
The iPhone Dev-Team has updated RedSn0w with the ability to save iPhone unlock tickets (SAM unlock).
redsn0w 0.9.10b8 adds the ability to backup arbitrary directories or files from your device into a zip file on your Mac or PC. The new button is Extras->Even More->Backup and it requires your device to be jailbroken with the afc2 service enabled (most jailbreaks include that). By default it will backup your activation records from /var/root/Library/Lockdown, which is useful for everyone taking advantage of today’s SAM unlock using Loktar_Sun’s trick