I too am trying to get ESXi 5.1 to run on an HP server with a Smart Array B120i controller.
HP seems to have a KB article that says that these controllers are generating errors in all versions of vSphere past v4 that relate to being unable to write kernal dumps to local storage. They do not mention that the need for the kernal dump is because ESXi 5.1, as it ships IS NOT COMPATABLE with the Smart Array B120i controller. It crashes every time it trys to load. Every time.
The work around of course, it to have the time and the resources to create a custom image with the driver that does work with this controller. Nice!
The HP web site is full of products that contain this controller and list themselves as "VMWare Compatable". Of course, what they do not tell you is that it is only compatable with VSphere from two or three versions ago.
Do not buy ANY HP servers that use the B120i Smart Array controller if you intend to install ESXi 5.1.
Way to go HP!! I think I will be calling Consumer and Coporate Affairs over that bit of false advertising.
RE