You can change system file of ipod touch. Dfu /device firmware upgrade mode is useful for downgrading to earlier version of ipod ios. The device is not responding The boot loop leads to a failed boot What iPhone problems can DFU mode fix? 5 iPhone issues that can be fixed with DFU mode. Here are some iPhone issues you can fix with DFU mode.
It has the most profound possible recovery for iPhone and is even more effective than putting the device in Recovery mode. DFU mode is a unique iPhone state that you can use to reinstall all software and firmware lines on your device.
