My RFX9600 has firmware version 1.4.8, which was the last (and beta) firmware that was released by Philips. Wondering if it's worth trying 1.4.7 (last official release). 1.4.8 is also the firmware that is on my RFX9400, which I tested recently and also got Command Failed when using it.

For Apple TV, I use a combination of the IR that you posted, and IR from an old Dune remote which I taught to my Apple TV. I do get Command Failed with the Apple TV, but I get Command Failed much more frequently with my Nvidia Shield Pro (2019). The Shield doesn't actually have IR built-in. I use IR via a Flirc USB stick. I feel that "Command Failed" feels happens maybe three times more often with the Nvidia Shield compared to the Apple TV.

The interesting thing is that I get Command Failed mainly with IR commands. I don't really notice it with RS232 and IP commands. The Command Failed problem got so annoying last week that I took out my old Harmony remote & hub from retirement (which I last used more than 5 years ago mainly for the kids' use). I actually created a VM a few years ago that runs a server that can query/control a Harmony hub via HTTP ([Link: github.com]). There were a couple of Shield commands that weren't available via Flirc, but were available only via bluetooth, so the VM was nice to have. I brought that VM out of hibernation, and my Pronto uses it as a getHTTP to bluetooth translator for commands not available via the Flirc USB. One thought I had was to use it for other commands instead of the Flirc IR equivalents.

So, yeah, using getHTTP is much more reliable. The Harmony hub also uses bluetooth to talk to the Apple TV, but Apple TV IR commands are fine, at least compared to Nvidia IR commands. I suppose the main disadvantage of using IP instead of IR are for commands that need a press and hold. For example, press and hold of cursor up/down/left/right commands don't work (don't repeat) for IP commands or RS232 commands.

Anyway, my Linksys WAP54G is arriving tomorrow (I wish I hadn't thrown away my old one years ago). So, next step is to try RFX9600 v1.4.7 or Linksys WAP54G.