I had my MXQ pro 4k for about 3 months. Worked great then yesterday I turned it on and it just sits at boot "mbox" logo forever. I tried booting in recovery mode and clearing cache and did a factory reset. Didn't work. I then used Burging Tool to try and update firmware but my computer will only recognize the USB connection for 2 seconds. Shows un known device then disappears.. when in recovery mode I get the message "E: failed to mount /sd_card (unknown connection)" not sure if that has anything to do with connection to computer as I'm using a USB to USB cable.. any help would be greatly appreciated