IIRC, there were several smartphone SoCs that dropped 32-bit ARM support from most but not all of their CPU cores. That was straightforward to handle because th

IIRC, there were several smartphone SoCs that dropped 32-bit ARM support from most but not all of their CPU cores. That was straightforward to handle because the OS knows which instruction set a binary wants to use. Doing anything more fine-grained would be a nightmare, as Intel found out with Alder Lake.