The VMware Knowledge Base provides support solutions, error messages and troubleshooting guides
Boot Information Is Lost If MBR Location Is Changed During Upgrade (5089096)
If the master boot record (MBR) location is changed during an upgrade from ESX Server 3.0 to ESX Server 3.0.1 or later version, boot information is lost. Attempting to boot the ESX Server host results in a GRUB boot prompt.
When upgrading from ESX Server 3.0 to ESX Server 3.0.1 or later version, do not select a new location for the MBR. Keep the location you used when you installed ESX Server 3.0.
In ESX Server 3.0.2, the installer is enhanced to always select the location where the MBR was previously installed in ESX Server 3.0 or 3.0.1.
Request a Product Feature
To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.