When I fly indoors, eventually my Tello will ascend rapidly on its own and crash into the ceiling. It does this just about every flight session. I am using the Gamsir T1d controller with an Android phone. I've calibrated the drone (including center of gravity) and it has the latest firmware installed.

Hey Snargfargle， sorry to hear that. For further analysis, could you show us a video performing this issue? Thanks a lot in advance.

RYZE Posted at 1-19 23:23
Hey Snargfargle， sorry to hear that. For further analysis, could you show us a video performing this issue? Thanks a lot in advance.

I've ordered a full cage protector. As soon as I get it I'll try flying indoors again. Someone elsewhere told me that it might be Bluetooth interference with the Gamesir. I flew the drone outside today, away from other Bluetooth devices, with no problems.
Oh, and I calibrated the Gamesir too. I'll keep you informed on the issue.