The iPhone Dev-Team has released RedSn0w 0.9.6b5 for unlockers stuck at the 05.14 or 05.15 basebands.
The new redsn0w 0.9.6beta5 is out. It gives both Windows and OSX users the ability to flash the iPad 06.15 baseband on iPhone3G or iPhone3GS. It fetches the baseband files directly from Apple for now (the only IPSW you ever point it at is the stock IPSW for the FW on your iPhone right now). There may be a long delay while it’s doing this (their servers are currently getting pounded).
Redsn0w is a cross-platform jailbreaking tool for iPhone and iPod Touch. New version redsn0w 0.9.2 supports the latest firmware 3.1.2.
redsn0w 0.9.2 supports:
All iPhones and iPod touches
Windows and Mac OSX (x86)
Apple firmwares 3.0 and 3.1.2
We expect to see Linux version quite soon.
If you need a carrier unlock, redsn0w will handle iPhone 2G by itself (by installing the BootNeuter utility). For the iPhone 3G and iPhone 3GS use Cydia after you’re jailbroken to install ultrasn0w (baseband 04.26) or blacksn0w (baseband 05.11).
If you have a late-model iPhone 3GS, or if you have an iPod touch 2G whose serial number begins with “MC” (newer than week 40 of last year), or any iPod touch 3G, you can use redsn0w to jailbreak but you are currently restricted to “tethered” rebooting. That means you need to connect your device to a computer each time you boot it – so just try no to reboot.
You can download the latest version of redsn0w here.