how to solve this, i am stuck with error 21 while restoring iphone4. my phone not responding for any action . And its not switching on
iPhone 4, iOS 7.1
Posted on Mar 15, 2014 10:47 AM
Q: stuck with error 21 while restoring iphone4
Is it charged ? Charge it on wall charger over night.
See this
http://support.apple.com/kb/TS3694#10
Appears to be hardware malfunction.