System Booting Kernel from Secondary Drive

[Laurie Jennings]

I'm having a problem with a Supermicro system running FreeBSD 9.1. Sometimes when I upgrade the kernel in my main drive (ada0), 
the system boots the kernel from the 2nd drive. It only happens sometimes. ada0 is mounted. but the system is running the old kernel. 
Pulling the 2nd fixed the problem.

What can cause this to happen? Is it a supermicro problem (it's a 5017R-MTF superserver) or is it something with FreeBSD. 

thanks in advance,

Laurie