I did a complete RouterOS upgrade on Mikrotik Hap ac lite.
The upgrade probably did not go correctly, two LEDs remained lit (PWR + USR).
Nothing can be done with them, even a central reset to factory settings does not help.
Can you advise?
You need to perform a netinstall.
You will probably need a lot of patience and several attempts, see here as a reterence:
http://forum.mikrotik.com/t/hap-ac2-not-working-after-7-14-update/174358/6