Thank you for using Cypress Developer Community.
Let me clarify the situation.
- Are you sure the PMODE setting is USB boot (F11) when you do programming FW? Moreover, PMODE setting is SPI (0F1) when starting its FW?
- Have you tried CyBootProgrammer.img (located in "C:\Program Files (x86)\Cypress\EZ-USB FX3 SDK\1.3\bin") for test? Is it lead same result?
- Is hardware connection on your board between SPI Flash and FX3 similar to CYUSB3KIT-003 hardware?
- How did you check CY_FX_RQT_SPI_FLASH_ERASE_POLL is working without any issue? Did you check the return status of CyFxSpiEraseSector() API is CY_U3P_SUCCESS?