I tested VIN-GND voltage when Bone is powered up with a dongle, and it’s within spec. So I am not sure if the problem is due to the power supply not being able to deliver enough current. I wonder if this has to do with EMI from the switching regulator and inductor. If so, using a USB extension cable to place the WiFi dongle away from the board may help. When I get time, I will try some experiments to figure out the exact cause