VCenter UM 5.1, upgrade Esxi 4 Host to 5.0

[mloraditch]

We are an MSP and have a central Vcenter 5.1 server for all of our clients who have a mix of ESX 4.0 to ESXi 5.1 licenses and hosts. I want to upgrade ESXi 4.1 hosts to ESXi 5.0, I am entitled to 5.1 but can only go to 5.0 due to vendor requirements (Cisco). I can import a 5.1 iso to UM but can't import a 5.0 ISO. Is there a package that is available that am I missing to allow me to do this?

Thanks!

[aravinds3107]

I can import a 5.1 iso to UM but can't import a 5.0 ISO

Is there any error message when you are importing ESXi 5.1 ISO

Check KB2004501 for differernt methods of upgade to ESXi 5.1

[mloraditch]

It's the 5.0 ISO that fails and I don't  have the exact text in front of me, but it just says it's not valid