Theoretically, sure. But practically, that would be (a) easy to catch happening, and (b) require the chip to fingerprint the relevant sections of machine code

Theoretically, sure. But practically, that would be (a) easy to catch happening, and (b) require the chip to fingerprint the relevant sections of machine code as implemented in multiple versions of the Linux kernel, and as compiled with innumerable iterations of compiler settings and versions. I don't want to say improbable, but I find it difficult to imagine otherwise.