My first post! Been using my ATV2 for a while now on 5.3 tethered. After several annoying power cuts decided to take the plunge into the untethered world!
I have the version of seas0npass taken from: http://support.firecore.com/entries/387605-Jailbreaking-101-Seas0nPass
This version is able to booth tethered just fine (so I guess it can find my device). However when I try to Create IPSW it will not find the device.