In your Booter code, set the first parameter of CyFx3BootUsbStart API to CyFalse.
(please refer to readme.txt in the FX3BootAppGcc Example project for more details)
Thank's a lot! I have understood and it works.
One more thing: In the documentation of CyFx3BootUsbSetDesc (Firmware API Guide, 1.3.3, page 164) the note says: "If the noReEnum option to the CyFx3BootUsbStart API is used, this API makes a copy of the descriptor to pass to the full firmware application". Do you have a hint for me, where I can access those descriptors in the full (U3P) firmware? I can't find an "U3P equivalent" to CyFx3BootUsbGetDesc(). How can I access those descriptors in the main firmware?