I have an ASUS K555L and it comes with a Mediatek MT7630E WiFi adapter which doesn't work out-of-the-box in Ubuntu. After looking in this very same website, I found a fix that worked, but I had to re-install it after almost every software update.
But now, after a kernel update (linux headers 4.2.0-42generic), this fix doesn't work. It throws the following error:
modprobe: ERROR: could not insert 'mt7630e': Required key not available
So, is there a way of fixing the fix?, is there a way to revert to my old linux headers?