Ed N6YN posted the following fix in the google group:

    With either patched firmware v2.032 or D13.020 installed in your radio...

    run Zadig, and install libusb-win32 (v1.2.6.0) or (libusb-win32 from: https://sourceforge.net/projects/libusb-win32/ as described in MD380tools / Windows-instructions.txt)
    Once the driver is installed you will see that if you issue a ./md380-tool spiflashid command, you will received either a # 1 or #2 from the above responses.

    Now, execute the "testlibusb-win.exe" file, then click on the Refresh button at the bottom of the popup window. (Note this file is located in the libusb-win32-bin-1.2.6.0\bin\x86 folder). Once you click on the Refresh button you will find that if you again issue a ./md380-tool spiflashid command in the MINGW32 window, you will receive the proper response from the radio:
    SPI Flash ID: EF 40 18
    W25Q128FV 16MByte

Now you can issue a 'make update flashdb' and your CSV file will be properly installed into the SPI Flash.

Close this issue once above fix has been confirmed and GNUWin32 instruction have been updated accordingly. Self assigning unless someone gets time to do it before me :)