We are building L4T from source and with custom configurations. In kernel_supplements.tbz there are some modules with version magics, for example tegra_config.ko. What might this be? Is there a possibility to get more information on what dependencies there are between the kernel and binary released supplements? There are also some modules, e.g. in lib/modules/3.10.40-gdacac96/kernel/crypto/, that can be built from source along with the kernel? What is the difference between prebuilt modules in kernel_supplements.tbz and the ones compiled from source?
The files from kernel_supplements.tbz are technically not needed for a Jetson board to run L4T (meaning mostly unmodified Ubuntu 14.04 LTS). Mainly these set up or add complete access to the tegra124 chip which would otherwise be limited (e.g., I think without this video might lose hardware acceleration or be relegated to a lower performance open source version).
For illustration, Jetson ships with R19.2 of L4T, which runs fine without running the update to install these files. The updater mentions the EULA on R19.2, separating the purely Linux portions from the nVidia-owned files (a requirement to ship open source/free while allowing the end user to choose to install non-free). Some of the content is publicly visible, e.g., firmware, and configures the non-public content. The rest of the content provides actual hardware access.