Unable to backup reComputer Industrial J4011 on Jetpack 5.1.1

I’ve been trying the script on a real device running Ubuntu 18.04 - I don’t see any reference to secureflash.xml in recomputer-orin-industrial.conf and I havent made any changes other than tweaking the script to fix the -e error.

These are the steps I’m running:

tar -vxjf Jetson_Linux_R35.3.1_aarch64.tbz2
sudo tar -xvf mfi_recomputer-orin-nx-8g-industrial-5.1-35.3.1-2023-08-04.tar.gz
cd Linux_for_Tegra/

# Apply patch for Jetpack 5.1.1 to fix the device name
wget -O orin_backup_restore.patch -c https://github.com/forecr/forecr_blog_files/raw/master/patch_files/orin_backup_restore_JP511.patch
chmod +x orin_backup_restore.patch
sudo patch -p1 -i orin_backup_restore.patch

cd ..
sudo cp -rn Linux_for_Tegra/* mfi_recomputer-orin-industrial/
cd mfi_recomputer-orin-industrial/
sudo ./tools/backup_restore/l4t_backup_restore.sh -b recomputer-orin-industrial

The patch file is from these instructions:

However I get the same error (the second one in my initial post) whether I do these additional patching steps or not.