Ralink MT7601U (148f:7601) Wi-Fi adapter not working on Ubuntu 16.04

Question

I have updated my Ubuntu desktop from 14.04 to 16.04 and my Wi-Fi dongle stooped working. I've tried to follow the instructions given here but it did not work.

How can I make it work again?

Thanks guys.

EDIT

So far I've run these commands:

rfkill list all
sudo modprobe mt7601u && dmesg | grep mt76

The result was:

[   85.231948] mt7601Usta: module verification failed: signature and/or required key missing - tainting kernel
[10822.191654] usbcore: registered new interface driver mt7601u

Any idea of what to do next?

EDIT2

I disabled the secured boot and it's still not working.
The result of running the previous commands again is:

[  185.695417] mt7601u 3-4:1.0: ASIC revision: 76010001 MAC revision: 76010500
[  185.712356] mt7601u 3-4:1.0: firmware, attempted to load /lib/firmware/mt7601u.bin, but failed with error -22
[  185.712362] mt7601u 3-4:1.0: Direct firmware load for mt7601u.bin failed with error -22
[  185.712865] mt7601u: probe of 3-4:1.0 failed with error -22
[  185.712917] usbcore: registered new interface driver mt7601u

Answer 1

The problem was apparently the kernel that was corrupted because other stuff did not worked as well. I erased Ubuntu completely and than reinstalled 16.04 and the Wi-fi dongle just works and no special installation to be done.

Thanks anyway for checking and putting your comments.