Redsn0w 0.9.9b9d fixes old bootrom 3Gs issues
Shortly after the release of Redsn0w 0.9.9b9, MuscleNerd announced that the newest version of their jailbreak tool would cause issues for old-bootrom 3Gs users. To remedy that issue, they have now released Redsn0w 0.9.9b9d. If you don't have an old-bootrom 3Gs you don't have to worry about this new release. If you DO have an old-bootrom 3Gs and you used Redsn0w 0.9.9b9 to jailbreak, you will have to download and re-run this new version but you can do it right over the top of your current jailbreak so as not to lose anything.
Update #17d: iPhone3GS owners in our comments section below noticed a problem with the untethered jailbreak available for the old-bootrom 3GS. We’ve corrected that problem in 0.9.9b9d. If you have an old-bootrom 3GS and have already used last night’s redsn0w on it, you can re-run it again without losing anything. Just use this new version, go to Extras->IPSW and manually select the 5.0.1 IPSW, then go back and Jailbreak it again (but you can uncheck Cydia because it’s already installed).