iPhone 3GS Help!

[Revoke]

Okay, My iPhone 3GS has messed up really bad, I want to keep it on 4.2.1& for some reason, it just stays at the apple logo with a kind of loading screen until it runs out of battery,

I can't restore it for god knows what reason but I tried to open TinyUmbrella and all I get is a startup error.

Does anyone know how else I can restore it or something, thanks,

Also, I tried the 'hosts' file way and it did not work.

 

[Applejuiced]

Did you install the iPad bb in order to unlock?

 

[awadeee]

If you've got SHSH, DFU restore to 4.2.1.