3gs iphone in perpetual black screen of death.
I have purchased a new 3gs iphone(new boot rom i.e iBoot-359.3.2). I jailbroke it with redsnow and it started working fine. It was a tethered break. But after some days I messed up with my iphone while restarting it. I accidentally chose (NO option for redsnow software instead of YES) and it went into the black screen of death. I think I have saved my SHSH keys but somehow now I am unable to retrieve them umbrella. I tried to restore to 3.1.2 only to get an error "it is not authorized for this version". I tried to restore it to 3.1.3(apple version) and remove the usb cable once I get the apple logo. After getting the apple logo I tried to restore the custom 3.1.3(activated) firmware but I am getting 1604 error. Please help me how to go further in succesfully restoring my iphone. I am fine with just jailbreaking for now (i.e for unlocking I am ok to wait). Is there any way to get my iphone working atleast as an Ipod.