Correct vShere Images for IBM Flex System x220 Compute Node (PureFlex)

We need to figure out what is the correct software packages to use to upgrade the following hardware:

• IBM Flex System x220 Compute Node (PureFlex) : CPU Series:Intel Xeon E5-2400 Series
• from vSphere v 5.5 to v6.0 U2. (currently running the IBM 5.5 image)

Do we use the generic package listed under the Product Downloads tab or the Lenovo System x Custom Image for ESXi 6.0 U2 Install CD listed under the ISO tab?

The following URL is from the Compatibly Matrix, but does not mention a custom image.

http://www.vmware.com/resources/compatibility/detail.php?deviceCategory=server&productid=19408&deviceCategory=server&details=1&partner=43&releases=275&systemTypes=1&page=1&display_interval=10&sortColumn=Partner&sortOrder=Asc

Thanks