Downgrade with xcode

[milesneptune]

I have my UDID registered and I am trying to downgrade with xcode but I get an error: The Device is not Eligible for the Requested Build. I am on Snow Leopard 10.6.3 and I have the 4.0 SDK. I have tried downgrading from 3.1.3 to 3.1.2 it doesn't work. I have also tried 4.0 to 3.1.2 it doesn't work. Someone please help me.

Thank you

[z3r01]

You have to DFU restore ...now if your on a 3GS and don't have your shah files saved then that means that your only option is 3.1.3 i think...i had this same issue...

[milesneptune]

oh im on a 3gs and i heard that you could use xcode to downgrade to any firmware that the device supported because developers have to test their apps