i keep getting error code 4013

1. Install the latest version of iTunes. The most common cause of iPhone error 4013 is software. Because iTunes is essential to both restoring and updating, you must have the latest version of iTunes. You could be running into this error because your version of iTunes is out of date. A simple, free software update may solve the problem. Update iTunes and try again.
2. Force restart the iPhone or iPad. A seemingly difficult problem with an iOS device is solved by restarting it. Sometimes the problem is a temporary software glitch that the restart will fix. In this case, you want a force restart or hard reset, which is a more complete reset. Then try the restore or update again.
3. Connect the device to iTunes and update it. If the error hasn't been fixed after the first two steps, connect the device to a computer using a USB cable. When you do this, iTunes should ask whether you want to update or restore your device. Select Update.

Tried 5 times solving 4013. Changed a different cable, Internet was stable. Even tried using factory reset. I m losing patience with apple. Each and every software updates and i m facing these issues.

Went to the store today for the same issue (Unknown error code 4013). It's not very "unknown" because the service technician immediately told me my phone is bricked and that I have a bad logic board. She tried to do a restore with the store's Macbook and got back 4013 and that was it. No additional tests or diagnostic of the hardware. She tried the same restore process as I did (outlined in the article) and said that it's not fixable.