IPhone 4s restore help?

[chry_cool]

I recently purchased an Iphone 4s from Ebay with the knowledge that it was stuck in a boot loop and would hold charge.
I'm, having problems restoring the phone to the factory settings it must have been jail broken before and I'm not sure what
firmware its running tried the shift restore on ITunes with the latest firmware but i get error 21.

Any suggestions of how I can restore the phone???

P.s tried re-jail breaking with absenthe, redsn0w etc but it doesn't work...

 

[h2olover1]

are you restoring in DFU?

 

[chry_cool]

I think I've tried that but i'll check again!

 

[chry_cool]

Doesn't work goes through the extracting software phase, makes the connected and then disconnected sound twice and then says error 21?

 

[h2olover1]

you need to be in DFU to restore a bootloop phone