Hanging on "Initialising IOV" message after ESXi 5.5 Upgrade

For my experience in ESXi infrastructure, it's always not easy to upgrade in one go.

Simply add boot options at bootup screen by pressing Shift + O, enter additional parameter "noIOMMU" at the end of the boot string. Then press ENTER key to proceed bootup procedures:

.
[Boot options...] noIOMMU
.

Once ESXi box is started successfully, you may want to apply persistent settings by SSH remotely into the box and issue the following command:

~ #
~ #
~ # esxcli system settings kernel set --setting=noIOMMU -v TRUE
~ #
~ #

This makes noIOMMU option survives ongoing reboots;-)