It sounds like you are using 0x6000_0000 for FlexSPI1, as 0x7000_0000 for FlexSPI2 at is already used for the NOR flash integrated into RT1064 SOC. PLease let me know otherwise. If this is the case, here is my analysis:
The SPT ( for short ) will not allow you to write additional images into the 0x6000_000 adress space.
Or allow you to change FlexSPI interface .
The reason is that the SPT creates a bootable image, and the RT1064 can only boot from 0x7000_0000 address space of FlexSPI2,. The SOC desing it does not allow you to boot from FlexSPI1 at 0x6000_0000.
If you want to use a tool to write to the external flash at 0x6000_0000 it is possible. The important thing is that you need to initialize the FlexSPI1 and the FlexSPI pins. The goods news is that we already have an SDK example, it is the evkmimxrt1064_flexspi_nor_polling_transfer this example already does this and it is a good starting point to know what you need to do write into that external flash.
As I mentioned before the SPT is limited and only writes to the internal flash at 0x7000_0000. If you want to write at 0x6000_0000 you will need to follow what the above demo does and have FlexSPI1 initialized. This migth imply to have flashloader project, that does this and receives the data to be programmed at 0x6000_0000, where the 64 MB memory lies. Per my understanding some work needs to be done to get your external flash, but it is not too complicated.
Please let me know your comments or any questions you may have.
Diego
