You could clone, fix this on the clone, and then flash the fixed clone. This isn’t too hard, but it takes a lot of disk space and time. Normally I advise people to test via an added entry in extlinux.conf, while leaving the original entry alone (thus having a backup boot option).
To get a clone, from the “Linux_for_Tegra/” directory:
sudo ./flash.sh -r -K APP -g my_backup.img jetson-agx-xavier-devkit mmcblk0p1
In the above the target expects an AGX Xavier dev kit. This will produce two files, my_backup.img and my_backup.img.raw. To find out more about this, including examples of loopback mount and examination:
https://forums.developer.nvidia.com/t/how-to-make-image-snapshot-of-agx-orin-and-restore-it/268304/2