@duncan Hi,
Thanks for everything, and we'll surely check all the feedback from loyal customers and optimize it in the further update, please stay tuned.
We'll be working on a new phone app for projectors, that would take time for more testing process, please be patient.
USB port can only be used for phone charging or USB disk. It can't offer the required voltage and current.
Same reason--Halo needs 19V 4.74A for normal running, that's why. And Halo's brightness feature needs enough power for a better viewing.