Comment # 3 on bug 1132956 from Jeff Mahoney

Overwriting kernel memory is never a solution.  The kernel now has the ability,
with compiler support, to randomize structure layouts.  utsname is one of them,
so this approach was going to turn from a bad idea to worse pretty soon anyway.

If my understanding is correct, you want to force newer hardware to report that
it's older so that "naive" build processes will work to build for the old
hardware.  You want this to be as cheap as possible.

Would adding a kernel command line option be feasible for your workflow?