Hello,
was also looking for a solution to flash JP6 to my Orin NX 8GB. Found a way to flash it.
Basically I have used this how to:
https://wiki.seeedstudio.com/reComputer_J4012_Flash_Jetpack/
Modification I had to do in order to make it work.
Step 1: download latest driver from here: https://developer.nvidia.com/embedded/jetson-linux-r362
Step 3: folder structure changed to:
cd Linux_for_Tegra/bootloader/generic/BCT
Step 6: again the folder structure changed and you should not use the --network parameter. Also the conf file name changed from p3509-a02+p3767-0000 to p3509-a02-p3767-0000.
sudo ./tools/kernel_flash/l4t_initrd_flash.sh --external-device nvme0n1p1 \
-c tools/kernel_flash/flash_l4t_external.xml -p "-c bootloader/generic/cfg/flash_t234_qspi.xml" \
--showlogs p3509-a02-p3767-0000 internal
Thats it.
Best regards.