It's the compact flash solution that isn't working for him, so I doubt it's his netboot code?
I also was under the impression that the security pic for netboot and compact flash are different.
I know official firmware is only able to use a specific brand of compact flash cards.
Maybe the firmware update didn't succeed and that's causing the issue? (As the problem is posted here I assume they did a firmware upgrade to this version)
So, what firmware version is it showing? What error is it showing in compact flash mode?