iOS 5.1 jailbreak is possible with multiple different tools now including SnowBreeze and RedSnow, only tethered jailbreak of iOS 5.1 is possible with both the tools. Snowbreeze works only on windows pc to create a custom iPSW firmware file from your original ipsw file.
Snowbreeze 5.1 jailbreak is a tethered jailbreak, except for iPhone 3GS old-bootrom users gets an untethered jailbreak. You can restore your device using iTunes and the custom IPSW file created by Snowbreeze to tethered jailbreak your device, now iPhone 4s and iPad 2 are not supported.
Snowbreeze 5.1 Jailbreak Download :
- Snowbreeze 2.9.3