[imtringued]

>Was the idea of an open ISA leading to an open SoC was just wishful thinking?

The boot process for RISC V is standardised. There are going to be far more RISC-V SBCs that support uefi than ARM SBCs.

[kramerger]

The boot sequence is standardised on all CPU architectures. But is the boot firmware (and specially the M-mode fw) open on all devices?

ARM addressed this by creating ATF which most companies now use:

https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/