Please don't ship dtb files at all, including the kernel images. If firmware does not come with hardware description, that is a shortcoming of the firmware. If a newer kernel cannot be booted with an existing device tree, then that is a bug and the kernel should be patched.
Ok, so in your world a distribution should not ship any dtb files, because the manufacturer's firmware is bug-free and feature complete on day one.
That's nice, but doesn't sound like the real world at all. > By all means, put a tree of verified actually working device trees > somewhere for platforms known to be provided with bad versions from > their manufacturer.That tree is the sum of the dtb files of the corresponding kernel, which this bug report is about. Those may not adhere to your definition of verified, but please don't forget that there're two separate worlds out there: upstream and downstream. Debian's current way of booting a kernel release with its dtb ensures those world never collide, and I think that is a very wise choice.
I don't know what devices you work on, but I have a couple of different consumer armhf and arm64 devices, spread out over different architectures. All their device trees are updated every single kernel release. Often it's for new drivers like mmc, pci, net, dri etc., which obviously the installer could make use of. Bindings are merged with the driver, so of course I want the dtb matching its kernel!