Dear,
I have suspect about eFSU on cisco 6800 using Quad-Supervisor (SUP-6T) but I'm not sure is support.
By information below link I found "Quad-supervisor SSO (VS4O) supports eFSU upgrades. You can upgrade or downgrade your VSS system using ISSU."
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/15-3SY/config_guide/sup6T/15_3_sy_swcg_6T/virtual_switching_systems.html#56355
But in deep detail I need to clarify some Restrictions for eFSU say "eFSU requires two supervisor engines, one active and one standby."
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/15-3SY/config_guide/sup6T/15_3_sy_swcg_6T/enhanced_fast_software_upgrade_efsu.html#24104
And issue command issu loadversion. I will specific active and stand by slot but in VSS switch will combined four supervisor.
Router# issu loadversion active-slot active-image standby-slot standby-image
Thanks for advise.
