Hi! Trying to install on DIR-2660 A2 without any luck so far.
Downloaded from here: https://downloads.openwrt.org/snapshots/targets/ramips/mt7621/
Tried with:
Ubuntu - Firefox
Ubuntu - Firefox Private Window
Windows - Firefox
Windows - Firefox Private Window
Windows - Chrome
Windows - Chrome Incognito
In all above cases I did get feedback that the firmware had failed.