Dear All,

I am no expert in iPhone devices but good in computers.

Suddenly, my iPhone rebooted and got stucked at iPhone logo with loading circle.
Details :-

Version - 4.1
Firmware or Baseband - 05.13.04

I am not sure about the Baseband version, as one of my friends had upgraded it to iOS 4.1 from iOS 4.0. I am not sure if he had modified the Baseband/Firmware too.

Please guide me how can I fix it and reinstall iOS 4.1 and jailbreak/unlock it.
Just give me trusted links to do this, there are so many links in google I am really confused which one to go for.

I DO NOT have anything important on the phone and have no worries regarding the data/contacts.

Please help.

Thanks in advance.

Best Regards

Step by step guides to jailbreak and unlock almost all versions of iOS can be found here:

iClarified - Jailbreak Wizard for iPhone, iPad, iPod, AppleTV
iClarified - Unlock Wizard for iPhone