Re: I *wanted* an Acorn Archimedes when I was at school...
"(only the Commodore series attempted a serious effort at making certain system calls portable across their range via their 0xFFxx kernel jump table, but the C128 used a Z80 to boot the system!)"
I think the same is true for all Acorn's pre-Archimedes BBC machines, including those with 16 and 32-bit second processors.
In fact it's the case on the Arc as well: in BASIC type A%=65: CALL &FFEE. It won't try to execute ARM code at 0xFFEE, it'll emulate the BBC's OSWRCH call and print the letter 'A' on the screen.