CYUsb.sys load before Mass Storage Device Driver | Cypress Semiconductor
CYUsb.sys load before Mass Storage Device Driver
I am writng some software to access our Cypress based memory stick on machines with the USB Mass Storage Devices disabled. This disabling can be done by deleting the actual USBSTOR.sys from a Windows machine. The problem is that the device is recongnised by Windows as a Mass Storage Device first and not a device based on CyUSB.sys EXCEPT if I set the VID/PID to 04B4/4617 in which case it does recognise the device first as a "Cypress EZ-USB NX2LP-Flex Unprogrammed NAND(3.4.5.000)".
I have taken the CYUSB INF file and changed the text and VID/PID to 04B4/1111 (I know I need a proper VID, but used this for testing). Using an memory stick (0b44/1111) not yet initialised with NandMfg.exe upon inserting it, an "unknown device" was found and Windows 7 evenutally installed the CyUSB.sys using my modified INF file. At this point NandMfg could see my device and I programmed it with the same VID/PID (04b4/1111). Upon reinsertion the device is not recognised as my device but a Mass storage device.
If I do exactly the same thing but set the VID/PID to 04b4/4617 using NandMfg.exe the Cypress CyUsb.sys is loaded and not the Mass Storage Device.
Why does my version of CyUSB.sys not load, but the "Cypress EZ-USB NX2LP-Flex Unprogrammed NAND(3.4.5.000)". driver does load? What am I missing to cause my driver to load instead of theMass Storage Driver?