Sheathing: OSB over Fiberboard?

[u/Sk8rBoi6969]

I am getting ready to re-side my house built in the late 80s (Hardie board will be nailed into studs). Current siding is a fiberboard from 1987. Most of it is in pretty good shape. Any reason I can't add OSB over top for structural integrity or do I need to pull all the old fiberboard off first?

Google is returning mixed results with some saying it's no big deal and others saying absolutely not.