The university I'm attached to used 68HC11-family dev boards for their intro embedded course until the early/mid 2010s, with a smattering of other platforms like 8051 derivatives in advanced classes, and have switched to ARM (Small Cortex M ARMs, typically TI TM4C123 TivaC boards) for almost all our embedded content since. Plus a few little Arduino based activities with the freshmen, though the form of that has changed over the years.
The intro to embedded systems course used to be only taken by Computer Engineers around their Junior year, since ~2017 we do it a semester or so earlier and make the EEs take it too as part of a streamline; EEs no longer take the computer architecture course, and the new embedded course covers some basic architecture concepts.
We still do the beginning of the semester in Assembly (we really only show them ARM Thumb) and the later part in C.
Possibly the most revelatory thing about that course is that the low-level view means we find out and try to correct that most of our students (as second semester sophomores who have in theory passed at least two programming courses and a digital logic course) haven't the slightest idea what code actually means/does.
Example: Every semester I've been involved, when we transition from assembly to C, we give a simple assignment to sort some arrays of (well documented) structs by a specified field and order, given the address where first element starts and length in elements, in both C and assembly. They are handed a starter project with a lightly-obfuscated object file that sets up the arrays, calls two provided function headers for them to fill in, then tests if the sorts succeeded. Details get changed every semester because students cheat compulsively on programming assignments, but it's always set up to be easy, the structs they handle in ASM are always 16 or 32b in length, stored aligned, etc.
Many of them... struggle mightily for two weeks because they haven't actually retained anything about number representation, memory (size, layout, byte addressing), arguments, the difference between a value and a pointer, and so on. The course staff spend weeks doing patient remediation around that point in the semester. At least we get a chance to make another pass over that material and more of them get it after.