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For Windows, see section "WinUSB driver and Zadig (Generation2, Generation 3, Cypress default and/or custom firmware)" and "LIBUSB versus CyUSB.sys" of Device Driver Layer.
For Linux, see Linux_FUT.
For Mac OS X, see "AN74505 - EZ-USB® FX2LP™ - Developing USB Application on MAC OS X using LIBUSB".