Can i do untethered JB on iPhone 4 with iOS 5 (not 5.0.1)

[raksrules]

I have an iPhone 4 with baseband preserved to 1.59.00 and iOS 5. This phone has been unlocked with ultrasn0w. Can i apply the untethered JB while staying on iOS 5 as i do not want to update the phone to iOS 5.0.1 as i don't find any such issues with 5.0 and also i fear that i may do something wrong and update the baseband and loose the unlock.
When i had purchased the phone, the previous owner had already upgraded to 5.0 while preserving the baseband and i am an iPhone noob and do not understanding much about upgrading, restoring etc.

[hcgaloi]

You can follow the instructions directly from the hackers. They are the ones that release Redsn0w here Dev-Team Blog

[xtacy]

U should update to 5.0.1 using a custom firmware. I think the latest redsn0w has that feature. Or u can use the latest sn0wbreeze and make a custom firmware. Restore using it and then install corona from Cydia.