I don’t know if the change you are looking at actually moves everything to the SD card…someone will have to clarify. Typically some of the partitions would still remain on eMMC even if you flashed to mmcblk1p1 (SD card) as the flash target.
Now if you happen to know what partitions need to be on the SD card, then there is a reasonable possibility that creating these manually on the SD card with gdisk (and setting labels) to match what is in a regular eMMC partition setup would do the job (followed by dd to copy each partition out of the eMMC as a binary file, and then dd to write back into the SD card…this could be done on a separate host or on the Jetson directly). You can list existing partitions and their labels via “sudo gdisk -l /dev/mmcblk0”. You might look at IDs via the “blkid” command.
Since I do not know about that pin, can someone from NVIDIA suggest what partitions other than rootfs might be changed to SD card when this pin (D7) is triggered as in #21? Or which partitions will always be required to stay on eMMC?