The ios 4.21 is the latest OS from apple where lot of issues were encountered by iphone/ipod touch/ipad users. Using RedSnow and Ultrasnow you can jailbreak or unlock this ios 4.2.1 from apple for Iphone 4, iphone 3Gs, Iphone 3G, Ipod Touch and Ipad.
Download RedSnow 0.9.6b5 Beta 5 - Link 1
Download UltraSnow 1.2 - Link 2
You can download Redsnow 0.9.6b6 here.
For Macintosh Redsnow 0.9.7b5 click here.
