Well, the above solutions are actually based on trial. It is because you may have difficulty in figuring out where the error exactly lies. If you try all the above methods but none of them can work out, a dependable third-party software called Joyoshare UltFix can be considered.
It can fix various iOS system issue without the risk of data loss. Also, its powerful repairing features enable it to solve such problems with two modes. With "Standard Mode", you are permitted to repair ordinary iOS issues causing no data loss. Besides, "Advanced Mode" is used to restore your iPhone to factory settings if you forget the screen passcode suddenly.
What's more, Joyoshare UltFix provides a free option to let your iPhone enter or exit recovery mode with one click. Except for fixing iPhone system failures, it also has the ability to repair many system issues with iPad, iPod touch and Apple TVs. The wide compatibility makes it support both the recent iOS 12.4 and all iOS devices.
Key Features of Joyoshare UltFix iOS System Recovery
Make iPhone 4013 error fixed without losing your data
Support a series of iOS devices and the latest iOS version
Provide free single-click enter/exit recovery mode feature
Fix varied iOS system issues with standard mode and advanced mode