Wow. That's irresponsible. If they know it not only doesn't work but results in a non-working remote, they should include a "Linux" button with a clear warning that it's not only not supported, but known to cause this. I wouldn't have even tried under Linux if I'd been aware. I lost 3 hours of time and started an Amazon return process because of that.
Thanks for the explanation!
Colour was a small factor, but I simply didn't need to support 4 devices. Really, I only needed 2. I wasn't aware the 6440 has a key backlight. If I replace it I'll upgrade.
I wish only that it had "next track" and "previous track" buttons separate from FF/rewind. I've mapped unused keys to cover that. Otherwise it's a good balance of simple design and enough buttons to be useful.