How to avoid the error 21 to restore the iPhone
How to avoid the error 21 to restore the iPhone
Thanks to the comment of Nina in one of our manuals to unlock the iPhone, we show another possible solution to solve one of the many errors that can be found in iTunes when trying to restore your iPhone with a modified firmware.
In this case, the error is 21, and which is caused by a process called iTunes iTunes Helper. To avoid this we must open the Activity Monitor application, as shown in the above image, select it and click Quit Process. It is also desirable before putting the iPhone into DFU mode and start the restoration have closed iTunes.