Honest question — why is it horrendous? It's cheap, reasonably capable, can be easily coaxed into doing most of what a person might want, and has enough adoption that advice and code is easy to find. I'm sure you mean horrendous in some more technical sense, but I've found it nothing if not practical. Please teach me.
- I/O is comically limited. Everything talking to the outside world is infamously bottlenecked on USB 2.0. (In comparison, any modern Rockchip or Allwinner SoC has Gigabit Ethernet directly connected to the SoC.)
- The memory subsystem is also a joke. 1 GB of slow LPDDR2 is the limit!?
- The boot process is absurd. A proprietary blob is loaded onto the GPU (!) from the SD card before everything else. An independent FOSS replacement boot stack project was started but not finished.
- And the firmware's support for network booting is very, very unreliable.
- There is a custom interrupt controller instead of the standard ARM GIC. (This was in fact one of the frustrations cited in the post about the open boot stack project's abandonment.)
- CPU crypto extensions (AES+PMULL/SHA1/SHA2) are absent. Other similar (4-core A53) SoCs (A64, RK3328) do have it.
- The GPU does not have memory protection. The VC4 driver does its best to try to validate shaders, but… LOL.
And here we're talking about Apple. They make their own SoCs. If they decided to get into IoT, they'd probably make a development platform based on one of their small chips they use in AirPods or whatever
I highly doubt this is for IoT advances, nor for internal debugging - because they have both already.
The watch, AirPods, all the 40+ processors in an iPhone, the chips in each and every dongle, Apple is way past starting in IoT. AFAIK the vast majority of cores do not run XNU though, which would further make this seem weird.
And for debugging, they just have actual iPhones that simply have the JTAG engine turned on.
I'm having trouble understanding what they could possibly want from any non-Apple SoC at all... unless their intention is really to make XNU on arm64 more open for developers and hackers. But I somehow doubt that.