Image Transmission Settings > Channel Mode > Custom is grayed out if the phone or tablet is set to some regions. At first I thought the limitation was caused by my old and semi-unsupported iPad mini 1 A1432 but the following thread provided the answer: Cant activate custom channel In that ancient tablet the Auto setting's fixed Transmission Quality 10Mbps(0.7km) doesn't update the tablet's screen properly -- only about 30% of the screen is updated every now and then... But the screen update is good after I changed the location setting to U.S. so I could set Transmission Quality to 4Mbps(3km). I understand that some regions might have regulations about permitted channels but why is also the Transmission Quality behind the region setup?? If I set my correct region, the DJI APP defaults back to 10Mbps with poor screen update. Litchi allows me to set 4Mbps. Previously I wondered why, after using DJI GO to set the camera, Litchi reverted to 10Mbps. Well, it doesn't if I set the tablet region to US. p.s. I am getting a new tablet: I have considered iPad mini 4 (A8 7.9") or iPad Air 2 (A8 9,7”). Both fit the DJI's stock RC controller. But I guess iPad Pro (A9 9.7") with 2GB RAM (like iPad Air 2) and Apple Pen support might be a better long-term investment. The new iPad Pro's screen brightness goes up to about 500 nits, an increase from the 400-or-so nits of the big iPad Pro and the iPad Air 2. iPad Pro’s screen is 40 percent less reflective than the Air 2. iPad Pro has a barometer -- when calibrated correctly it can be used to determine altitude, which might help GPS devices to lock on quicker and with greater accuracy. Now I must only decide if I want the cellular model with built-in GPS (really only needed for DJI's Follow Me intelligent mode, and dynamic home point) and how much storage I really need. 9.7-inch iPad Pro review: What makes something “Pro” anyway?