Updating my lab this week I realized my bios was out of date on my Brix devices and decided to flash them prior to the 5.5 u2 install. Nothing to much out of the ordinary here, but the one thing to make sure you check is the CPU Settings after you upgrade. It seems to turn VT-x off by default, so make sure you turn it back on!
That said, being upgrade time again I always make a custom ISO for my BRIX because the ethernet card that is installed is non-standard. Not much has changed in terms of creating this, but the EsxImageProfile changed to Date driven vs. build number. So just make sure you watch out for that. Below is what I used. From there I simply added this to my Update Manager and pushed it out to my hosts.
# Add VMware Image Builder Snap-in
# Add VMware Online depot
# Clone the ESXi 5.5 U2 profile into a custom profile
$CloneIP = Get-EsxImageProfile ESXi-5.5.0-20140902001-standard
$MyProfile = New-EsxImageProfile -CloneProfile $CloneIP -Vendor $CloneIP.Vendor -Name (($CloneIP.Name) + “-customized”) -Description $CloneIP.Description
# Add latest versions of missing driver packages to the custom profile
Add-EsxSoftwarePackage -SoftwarePackage net-r8168 -ImageProfile $MyProfile
Add-EsxSoftwarePackage -SoftwarePackage net-r8169 -ImageProfile $MyProfile
Add-EsxSoftwarePackage -SoftwarePackage net-sky2 -ImageProfile $MyProfile
# Export the custom profile into ISO file
Export-EsxImageProfile -ImageProfile $MyProfile -ExportToISO -FilePath c:\ESXi-5.5.0-20140902001-customized.iso