yes, first connect. Background (my guess): Telleo originally was only capable of 10m.
Only more recent firmware added support for 30m. So Tello App has to be connected to first check if you have a recent firmware, and then it unlocks the 30m
Only more recent firmware added support for 30m. So Tello App has to be connected to first check if you have a recent firmware, and then it unlocks the 30m