In order to avoid other peoples asking the same question... I opened a support case and finally got the answer:
... even if on the FX3 datasheet eFuse is mentioned as an option, it isn't available for "normal"/ low volume customers ! The only way to change PID/VID at boot is to boot FX3 using an external eeprom resident image.
Thanks for posting this here Joebre.
Just to clarify, I'm booting from I2C EEPROM with the "B0" image type, but there seems to be no way of changing the Cypress VID/PID other than using the "B2" image type, which then only uses the EEPROM for that, and then does not allow the firmware to be loaded from EEPROM as well.
Is my understanding correct, or is there a way to both boot from I2C EEPROM and also use our own VID/PID other than for high volume customers?
Could you any one please let me know how to create B2 image type?