ok，thx @WayneWWW
I follow your suggestion and it success to flash the new uefi but there‘s some thing wrong with uefi pictures.
so let list the progress.
I wanna to replace the uefi picture, so I follow the instructions as below:
then I rebuid the uefi source code according to the instruction: Home · NVIDIA/edk2-nvidia Wiki · GitHub
next I got BOOTAA64.efi and uefi_jetson.bin files and replace the file in bootloader directory.
finally I flash the whole image as you mention above.
after reboot I didn’t get the expected picture and it’s just black!
so if there is some thing wrong with my method, and any suggestion? thank you!