Can't restore iPhone iOS 4.2.1 ! Help please !

[sPwism]

I recently purchase my iPhone4 and jailbreaked it with RedSnow.

It appears that my camera flash light is faulty now as it wont turn on when i use my camera or any flashlight apps. I believe it's a software fault as i did not drop my phone and have been very gentle with it.
I have tried to reset the settings but the flash light still does not work.
I need to restore my phone back to factory state so that i can send it back for a warranty exchange.

However when i tried to restore with the iTunes, after verification with apple,error code " Your iPhone could not be restored, this device isn't eligible for the requested build 4.2.1 "

Would appreciate if i receive help and tips on this issue.
Thanks !

 

[yayitsezekiel]

have you tried putting your iPhone in DFU mode before restoring?

 

[sPwism]

Oh, DFU mode ? how do i put my iPhone into DFU mode ?

 

[sPwism]

Oh ok i managed to get it into DFU mode and it worked ! thanks !

 

[NathanA]

Interesting...the other thread I responded to in this forum had the same issue, also with an iPhone 4. I wonder if Apple's update servers are just being wonky...

-- Nathan