Some users were complaining about newly released iBooks for iPhone having issues on jailbroken iOS 4 devices. The good news is that Redsn0w has been updated to version 0.9.5b5-4 in order to fix this problem. The official change log is as follows.
Redsn0w has been updated to bring jailbreak support for the newly released final version of iOS 4 for iPhone 3G and iPod touch 2G. Available for both Windows and Mac, redsn0w jailbreak tool additionally also enables options for multitasking and background wallpapers on iPhone 3G and iPod touch 2G which otherwise are disabled by Apple.
Redsn0w 0.9.5 has been updated! which brings long awaited support for Windows users to jailbreak iOS 4 GM (formerly iPhone OS 4) on iPhone 3G and iPod touch 2G. Like the last release, this update also includes optional support to enable multitasking and wallpapers on iOS 4.0 on iPhone 3G and iPod touch 2G which otherwise are disabled by Apple.
The latest version of Redsn0w brings full support to enable multitasking and wallpapers on both iPhone 3G, and iPod touch 2G, running iOS 4 which otherwise are disabled by Apple, citing performance issues. We have already posted full detailed guides on how-to enable multitasking and wallpapers support on iPhone 3G and iPod touch 2G manually. If those guides are too long or complex for you, you can now use the latest version of redsn0w which gives you a one-click option to enable these options with ease.
Apparently, an ex-Apple employee has managed to successfully jailbreak iPhone 3GS on iPhone OS 4 Beta. The redsn0w 0.9.5 jailbreak tool for iPhone OS 4 currently works on iPhone 3G only. The support for other iDevices will naturally follow once Apple releases iPhone OS 4 at WWDC. But KaatjeNL’s jailbreak method works on iPhone 3GS too. And the best thing about it is that it doesn't upgrade your baseband, which means you can enjoy iPhone OS 4, fully jailbroken on the older baseband with an unlock using ultrasn0w.
Redsn0w has just been updated to beta 4 to support the latest iPhone OS 4 Beta 4 firmware. iPhone OS 4 Beta 4 was released by Apple last week, which since Beta 2 has closed the jailbreak loophole used by Redsn0w 0.9.5b1 and b2 to jailbreak OS 4. But with this latest version of redsn0w, you should be able to jailbreak iPhone OS 4 again on iPhone 3G.