Android - Unable to activate USB debugging after upgrading to Android 5.1.1
- Open settings and go to storage
- Press menu and go to USB Storage Mode
- Change to USB or MTP (NOT Charge only)
- Disable and re enable Development options with the 7 clicks on Build Number
Screenshots (click images for larger variants)
Removing 'persist.system.usb.config' file from data/property/ folder and restarting the device solved the issue for me.
After restart, the device shows the option to enable 'USB debugging'.
Root access is required to remove that file.