Perplexing DevKitC_V4 can't flash with CP2102 on windows but works on OSX

[RMandR]

I have a DevKitC_V4 that has a CP2102 on it.

On windows with MSys, make flash does not work unless I manually press the EN/Boot buttons. Make monitor works fine. The Huzzah32 Feather board that I have has a CP2104 and that one flashes without issues.

I know it's not a hardware issue with devKitC since make flash works fine in OSX.

So all of this points to the SiLabs Driver for CP2102 perhaps not being able to properly drive DTR, etc line for EN and Boot.

I've downloaded and tried SiLabs CP210x VCP driver version 6.7.6 and 6.7 and neither work for the CP2102.

Is there a correct magical sequence that can it going?

EDIT: This maybe a timing/capacitor size issue? I'm running these under VmWare which may change the timing of the USB-Serial calls.