Support helped me in a ticket with this one. Turns out I had to erase the flash by setting the boot configuration to Serial Downloader (via the boot configuration pins) and using this tool: https://github.com/JayHeng/NXP-MCUBootUtility to erase the flash. Don't forget to change the boot configuration back to whatever it was set to. Also note that the tool expects the board to be connected via the USB OTG port so that it can access it as a HID device.
in my case for the RT1020 and RT1050 instead of using NXP-MCUBootUtility I always changed the boot configuration to something not used and then run the flexspi hyper flash/nor example from internal SRAM -> the examples erase the complete flash memory if running from internal SRAM.
Hi Nicholas Sohacki ，
Thanks for sharing the ticket reply in the community.
MCUBootUtility also support the UART, not only HID.
Wish it helps you!
If you have the new questions in the future, welcome to create the new case, thanks.