The process to update FX2 firmware with an .iic file and Cypress's CyConsole
application is detailed in Wasatch Photonics
PRD-0105.
However, that document skims-over the process of unassociating the spectrometer
from libusb-win32 drivers and reverting back to the desired Cypress EZ-USB
drivers. Here's the short-form on how to do that.
Download the Cypress drivers from here: https://community.cypress.com/docs/DOC-12366
Use the Device Manager to "Uninstall" your libusb-win32 spectrometer. Make sure you tick the box to "Uninstall" the old driver. This will leave the device as a raw "Stroker FX2".
Instead of browsing your filesystem, "Let me pick" from the list of available drivers.
Tell Windows to show you "All" common hardware types.
Even if Cypress is listed as a manufacturer, go ahead and choose "Have Disk".
Browse wherever you unpacked the Cypress drivers downloaded from cypress.com,
then select the appropriate .inf (e.g. Drivers/Win10/x64/cyusb3.inf).
Pick the approrpriate Cypress FX2 model (e.g. FX2LP Development board).
Ignore the "Update Driver Warning" (click Yes).
You should now be able to run CyConsole and upload your .iic file using the EZ-USB interface and the "lg EEPROM" button.
(Remember that a full power-cycle (12V, not just USB re-enumeration) is required following a firmware update.)