Actually there were times when self-flashing was a question of changing files on a system partition. You got a kernel, device tree, initrd, rootfs. All on single SD card. Easy to access. Easy to swap. Update and reboot, done.
But today? Forget about it. You are required to press the recovery button and use an X86-64 based computer, because the binary tools exists only for this platform. There are encrypted device tree blobs in the eMMC, without which the system wont boot, because each newer L4T release will flash the bootloader (which in above metioned terms is really equivalent to the bios/uefi), and provides a set abstraction to the actual system loaded. But no. Nvidia choose not to support full system loading from SD and requires that the DT portion is flashed onto the cpu module’s eMMC. Without any clear reasoning why to do that. But the proof that it does not need to be that way is in the earlier L4T releases. A deployed application does not need to flash its bootloader/BIOS, but should be possible to flash itself. And that is no longer possible as it was before.
I do not believe there is any technical obstacle to provide features the users of this platform want, but there is a seriously bad management of these products in terms of support and development. Many things are left out undocumented, many things are getting more and more obfuscated. Instead of providing a platform which can evolve and develop, we are fed with false promises, impossible to achieve features and buggy hardware. There are uncorrectable bugs which prevent the TX1 and TX2 to be used in our serious application and we are quite tired of working with such a black box.
I always wonder why manufacturers are unable to listen to their users and try to push out products which do not serve the market. If anybody reads this from NVidia, please make a change and start supporting the products properly. Open up the documentation, open up your secret bug/errata/workaround database. We want to use these products but the only one stopping us is unfortunately you, NVidia.