The are two possibilities to restore iPhone.
1. iPhone Restore Mode
Follow the steps below to turn your iPhone in Restore Mode.
- Shutdown your iphone with the hard reset "home button and power for 10 second"
- Connect the usb cable to the pc but NOT to the iphone"
- Open itunes
- While the iphone is off, press the home button for 5-10 seconds then plus the other end of the white connection cable into the iphone
- Do not remove your finger from the home button
- iTunes will detect it and you can now restore it
In restore mode iPhone will load some additional software to verify that u will not downgrade your firmware(remember that u can press "shift" to manually choose firmware in iTunes).
In my case lib folder was corrupted and no additional software can be started in recovery mode. So...
2. iPhone DFU mode
Follow the steps below
- Connect your iPhone to your computer.
- Turn iPhone off.
- Hold power and home together for 10 seconds (exactly).
- Release power but keep holding home until the computers beeps (observed on a PC) as a USB device is recognized.
- A few seconds later iTunes should detect your iPhone.
- If the Restore Logo is present on the screen, you are in Recovery Mode, not DFU.
DFU is absolutely PC/Mac side controlled process, so that was the catch.