I believe I've discovered my problem: https://gist.github.com/AlexForster/0fb4699bcdf196cf5462
As mentioned previously, I have two X520-Q1 cards installed. It appears that initialization of the first card obeys allow_unsupported_sfp=1, but initialization of the second card does not. Is this a bug, or is there a way to work around this that I'm not aware of? Alex Forster
