Hey I have a 4s and iPad 2. I was able to successfully upgrade my firmware to 5.1.1 and then downgrade to 5.0.1. Redsn0w does a great job at downgrading and restoring but a not so nice job in jail breaking. I ran into the service not available error message on both my 4s and iPad2. A few times redsn0w read my phone as on 5.1.1 even though it wasn't. My advice is to restore/downgrade with redsnow and use absinthe to perform the actual jailbreak. I used absinthe only once without any issues. Any of you guys have an issue with jail breaking the correctly on the first try???