> There are standards for ARM, and they are called UEFI, ACPI, and SMBIOS.

The most popular ARM dev and production board - the Raspberry Pi - doesn't speak a single one of these on its own, so do many of the various clones/alternatives, and many phones don't either, it's LK/aboot, Samsung and MTK have their proprietary bootloaders, and at least in the early days I've come across u-boot as well (edit: MTK's second-stage seems to be an u-boot fork). And Apple of course has been doing their own stuff with iBoot ever since the iPhone/iPod Touch that is now used across the board (replacing EFI which was used in the Intel era), and obviously there was a custom bootloader on the legacy iPods but my days hacking these are long since gone.

I haven't had the misfortune of having to deal with ARM Windows machines, maybe the situation looks better there but that's Qualcomm crap and I'm not touching that.