Firmware not installing
If you get the black box with dots and lines when trying to update the firmware then the connection from PC to WM isn't working correctly and the tool is not seeing the right com port.
There are a couple of possibilities here.
1. USB cable not working. Always try the USB cable that came with your device first,
2. Incorrect COM port selection - Make sure you are using the correct COM port and don't have anything else commandeering it. We have had in the past someone who added an uncommon anti-virus software which prevented the COM port being accessed. Eventually it started working again once the offending software was removed.
3. USB Drivers might need installing/reinstalling (would check device manager to see if any conflicts exist) I have had this issue where I needed to uninstall USB drivers from computer, remove device from Device manager unplug wm4, reinstall wm4 drivers from tools, plug wm4 back in and it would work.