First, we have successfully compiled the images directory using the Release_to_customer.sh script, and then use make_usb_upgrade_sigmastar.sh to make the USB upgrade image:
#cd project
#./make_usb_upgrade_sigmastar.sh

After executing the above command, the USB upgrade image is successfully generated: project/image/output/images/SigmastarUpgrade.bin, copy this image to a USB flash drive, and then connect the USB flash drive to the board.
Then power on the board and enter uboot, set UpgradePort to 1:
#setenv UpgradePort 1
#saveenv

Finally execute usbstar to complete the upgrade:
#usbstar