I have recently built an ESXi 4 sever on a x3650. I saw on the support site that there’s an UpdateXpress package VMware. However I don’t know how this is run. From what I’ve read, you can’t mount a CD/USB or install anything within the ESXi shell.
This version of UpdateXpress System Pack Installer supports the following operating systems:
VMware ESX 3
VMware ESX Server 3.5 "
UpdateXpress System Pack v1.40 for VMware - IBM System x3650
http://www-947.ibm.com/systems/support/supportsite.wss/docdisplay?lndocid=MIGR-5080544&brandind=5000008