75XX Offboard Flash
From embeddedTS Manuals
This needs to be done directly on the SBC. You can find the latest SPI image here.
Backup
spiflashctl -l 0 -R 64 -z 65536 > spiflash.dd
Restore
dd if=/path/to/4mb-spiflash-latest.dd bs=512 conv=sync | spiflashctl -l 0 -W 64 -z 65536 -i -