i recently bought a tethered iphone 3gs on firmware 4.2.1 but tried downgrading it to 3.1 but gave me error 3194 now i want to restore it back to 4.2.1 but it keeps giving error 1015.
i have tried error 1015 fixer and failed.tried tiny umbrella to kick out of recovery and failed.tried ireb and failed.i tried irecovery and failed also.
please help.what should i do...

First error is 100% normal if you don't have saved SHSH - unless the previous owner saved the SHSH for previous iOS versions with Cydia then you will NEVER be able to restore to lower iOS versions.

Second is likely that the previous owner has upgraded baseband to 6.15 (iPad baseband)
See http://www.hackint0sh.org/f204/196391.htm for answers...

Thread closed (both questions have been answered hundreds of times previously, next time use the search function before creating a new thread)