Help iphone 3g 1015 error

Question

Friends on the forum after a long time of not having an iPhone, I get a very cheap indeed but came without upgrading, trying to upgrade remained in Error 1015 with the logo of itunes on the screen, try to release it also greatly appreciate the help ... It is a 3G IPHONE Version 4.2.1 Atnt brand .. 

 

 

regards

Answer 1

It gives you 1015 because it has the 6.15 baseband. 

 

You can do 2 things: 

A: one custom restore (do not give 1015) and then lower the bb to 5.13 

B: Restore to official 4.1 and when you take it out of 1015 with the tiny and then low to 5.13 bb