I have a Stranger Things Premium and was about to install a topper when I tried to open the backbox with no luck. To the best of my knowledge, it is not a key issue (correct key and the key actually allows the lock to turn about 10 degrees before stopping). My best guess is that the cam may be somehow misaligned and hitting the side of the cam opening as I can hear a "click" when getting to the end of how far the key turns. I have unscrewed the two torx safety screws and have fiddles with lifting the backglass every which way with no luck. I am hoping it is not time to drill the lock and was wondering if anyone had any tips/tricks/suggestions to try before going that route.

It’s the type where just the round part pokes through the speaker cover panel.

I have same concerns around drilling. Good thought, I’ll check and see if I can attack from different angle.