The initialization of the CPU, the control of its supply voltage and clock frequencies, the memory controllers and all the peripheral controllers, like PCIe, US

The initialization of the CPU, the control of its supply voltage and clock frequencies, the memory controllers and all the peripheral controllers, like PCIe, USB, display, GPU, video codecs, sound, video camera and so on. There is a huge amount of work needed to support any kind of computer, beyond the ISA of its CPU. All the device drivers required by a modern computer may total millions of LoC. Unlike for the Intel-AMD computers, for Arm systems few computers observe any standards, though Elite X implements ACPI, which made its initial support much easier than for the older Arm computers. With the help of ACPI, OpenBSD has succeeded to use NVMe (i.e. a SSD), USB (any peripherals) and the display as a simple frame buffer. This would be enough to use such a laptop as a server, but to use it as a personal computer a lot more would be needed. ACPI shows a ton of undocumented peripherals. Using those will have to wait the Linux support promised by Qualcomm. After open-source device drivers would be available, they could also be ported to any other operating system.