Lee, That is correct, they can be used for update as well. The labeling is somewhat misleading.  If you have any issues let me know.
Hi all, We are looking to update our hosts to ESXi 5.1 U1. I've checked the customized image on DELL's website and it states the download is for recovery / re-installation only.   Does anyone know if we can attach this to update manager and update the hosts ? This was the method for updating from 5.0 > 5.1 in the past.   Thanks in advance :)   Lee
ESXi 5.1 Update 1 - Attach to Update Manager ?