So I'm on my second Mi box now and both had/have the same issue: Upon initial setup, I was able to insert either one of my NTFS flash drives into the USB port to side load APK's without any problems. Now, upon inserting a flash drive, nothing happens. No pop-ups, nothing shows in ES-File Explorer, no lights on my flash drive illuminate to indicate power... nothing. I even tried the USB wireless adapter for my Logitech mouse (which worked fine) and that doesn't work either. Here's what I've tried so far:
-Factory reset
-Tried using NTFS/FAT32/ExFAT
-Exchanged my Mi box for another one and the same problem happened after system updates.
I'm not all that familiar with the Android system, so I looked at the running system processes and apps and couldn't see anything that was disabled that would prevent USB access.
Any ideas on how to restore USB functionality?
have you tried checking developer options?
checked if usb debugging was turned on. this happened to me once that usb was not properly working. Even after restoring factory settings usb port is still not working. enabled developer settings and found out that usb debugging was turned on. Disabled it and usb is back.