Iphone 3gs help

Faulty Apple iphone 3GS 16GB.
This phone has been dropped and the screen has smashed and now when I connect to itunes it says that the phone is in restore mode and needs to be restored but when I do it comes up with a ERROR 21 message.
Answer #1
have u edited you host files before to downgrade an apple device?
if so try and go back to delete the additional apple line in the hosts files and try to restore again.
otherwise you can always try to kick it out of restore mode by holding home and power together for 10 secs.
Answer #2
thankyou for that i shall try it nw. Wo_OT .. you online?
Answer #3
Error 21 can be hardware failure…
But you can try (obviously you don’t have clue if that phone has saved SHSH blobs) to update to 4.3.5 (latest released FW)….
Answer #4
Even If He Updates To 4.3.5 He Can Easily Downgrade To 4.1
Try Downgrading First.
Put iPhone In DFU . Restore To 4.1
Let me know which error message it is.
Answer #5
ok thankyou guys.