Has Apple stopped signing 3.1.3?!

[50thVert]

Hello all,
I am trying to wipe my 3GS so I can resell it and when I try to restore to 3.1.3 with iTunes 9.1.1 it says it is not possible. Has Apple stopped signing this package or is something else happening?

The error that's given is "This device isn't eligible for the requested build"

 

[Gizmotoy]

Sounds like you pulled the 3GS version of 3.1.3 or something. There's a different load for each hardware revision.

 

[spacehog371]

Yes, once a new OS is released Apple stops signing the previous OS.

The entire purpose of it is to prevent downgrading... what made you think that they wouldn't want to stop downgrading os4 to 3.1.3?