Just finished a troubleshooting session with operator setting up Xiegu G90. He was struggled with no audio from the transceiver. Turned out that it was due to the mode setting; it should be set to “U-D (upper side band digital)”. Older firmware like mine (1.75?) doesn’t have this option and works on regular USB (upper side band).
Other relevant G90 settings: line out level, line in level, and input source (line in for digital).
Tour of older firmware settings for digital modes: