I tried it on my OS Mio 4K... It works, but seems to refresh only every few seconds... Do you know if there's a way to make it refresh more often? Or any app that would do the same but closer to real time?
Sure, look on the bottom of the Screenshot in the WebIF screen, and you'll see a box you can tick called "Refresh automatically every 30 seconds".
Change that to anything you want. You can also tick another box for a higher resolution, which is just to the left of the other one.