Sample root file system

On L4T document, it says to run below command to have sample root file system.
sudo ./nv_build_samplefs.sh --abi aarch64 --distro ubuntu --version bionic

Then just after that, it says “Setting Up the Root File System” by downloading Tegra-Linux-Sample-Root-Filesystem_<release_type>.tbz2.

What is difference between them? Do I need run above two steps both?

I can’t answer completely, but the sample rootfs is a purely Ubuntu distribution without any of NVIDIA’s drivers. In part this means the sample rootfs is just an ordinary Ubuntu licensing scheme. It becomes the end user which places the binary drivers from NVIDIA into this, and thus a large part of modification to the rootfs is placement of drivers into that file system. This only needs to be done once, and occurs after the sample rootfs is unpacked.

In the past (long past) we didn’t have JetPack/SDKM to do the prep. We’d unpack the sample rootfs manually, and then run a script to copy files into place. Those were not package based, but eventually, with JetPack/SDKM, the “hybridization” of NVIDIA files into the rootfs became package based. Since this was being performed on a desktop PC for an arm64/aarch64 (the PC is not arm64) QEMU was put into the mix such that ordinary package tools (apt and dpkg) could run without any special hacks.

I don’t know the specifics of nv_build_samplefs.sh, but I imagine it is changing due to bootloader changes and migration to newer software, but the basic purpose is likely the same: Add target specific NVIDIA content to a completely generic Ubuntu filesystem.

So if I have a PC and install Ubuntu 18.04, then unzip Tegra-Linux-Sample-Root-Filesystem_<release_type>.tbz2 to <your_L4T_root>/Linux_for_Tegra/rootfs. Is it enough? I found the board can’t be booted if I just do these steps.

Do I need install SDKM on the PC to flash the board successfully?

For manual install you would unpack the driver package as a regular user, and then unpack the sample rootfs using sudo (as root). Following this you would run “sudo ./apply_binaries.sh” (there seems to be a new version of this for upcoming R34.x+) once to add NVIDIA content to the rootfs.

Once the above is done you can flash.

ok. thanks

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