iPhone hotspot dropping out after a bit

Camera JVC GY-HM890 set to 1920x1080p
Phone iPhone 7Plus on BoostMobile network

X2 works OK for a minute or so on iPhone hotspot, then goes offline. Shut off hotspot then turn back on and X2 is OK for another minute, then drops out again “Device Offline”

This DOES NOT happen when connected to a wi-fi network or Ethernet cable, nor does it happen when hotspotted to an android phone, so I am reasonably sure it is the X2 not playing well with the iPhone.

Any ideas?