@Andrew_Davis I didn’t know/realize you had this with your KW88 too?
I didn’t mention this very useful tip from +Saša Petrović .(sorry it (G+) doesn’t quite get the right link)
MT6577 USB VCOM drivers(I know we have a MT6580 but id did the trick and you put in a legacy hardware( device manager> Action > add legacy hardware) and you add the MediaTek DA USB VCOM port<<<
I did this and as I connected the watch (being completely off) it gave the watch (for a second ) another driver quit similar to this installed driver .
As if it doesn’t recognize it until you install the above driver and then when it does gives it his own suitable one.
In other words…the driver the watch needs to be recognized when its powered off (giving it a port)is a completely different one then when the watch is on (giving it usb access)
You can check with watch powered off if its connected although it connects only for a second and then beeps for disconnect it shows a battery on the watch for charging .
After that the most important thing is starting up flash tool (make sure to download the latest one SP_Flash_Tool_v5.1636_Win
Load into it under scatter-loading-file the latest FW for the KW88 (you know where to find) and remove the activation of the preloader (do NOT flash that one)
Hit the download button and connect put the usb cable in your pc (I still left it connected to the watch to make sure it staid well connected there) and leave it be for a while to flash (it shows on the progress bar)
If you have a laptop instead of a big-tower pc or something it may well be the power of the usb ports aren’t sufficient enough .(it’s a well-known fact and well documented all over the internet) you can borrow or buy a powered usb hub that’ll take care of that.
I have a disk docking station that also has 2 powered usb ports so I used that.
Pff …whole lot of words but I hope I explained it well enough and left nothing out telling how I did it after I cooled down and read all the help from the community 
Good Luck and Success !!
o and as for the connection loss with normal working watch on usb>>> I found out that when I restarted (reboot) the watch it connects and stays connected for a while. So if it doesn’t …try reboot.