In the past, when Dell provided their version of an update to Esxi, you could download it in the form of a zip file. You then applied it in this manner (from the esxi command line):
esxcli software profile update -d /VMware-VMvisor-Installer-7.0.0-15843807.x86_64-DellEMC_Customized-A00.zip -p DEL-ESXi-700_15843807-A00
When you go to the Dell website and attempt to download the latest version (Version 7.0, A02), the files are no longer there and, instead you are met with this message:
“Dell EMC has migrated the latest revision of the Dell customized ESXi images with customized drivers to VMware’s website. This change aligns with industry-standard practices and brings the Dell EMC-customized image to the same location as our competitors. For customers who manage heterogeneous fleets, this simplifies the procurement of SW images as they will all be housed in one location. Please go to your my.vmware.com license portal or click the link below to be redirected now. Older revisions of these images can be downloaded from www.dell.com/support in case there is a requirement
One you go to the link provided, you no longer have any file available except the ISO file. I know of no way to upgrade from the command line via the ISO file.