FYI - I was running into an error upgrading to ESXi 6.5 using the Cisco custom ISO's stating "CONFLICTING_VIBS ERROR". Seems to happen on every Cisco custom 6.5 ISO available through VMware:
To get past this, I had to do the following to the existing ESXi install:
From ESXi Console:
alt + F1 (to enter shell)
esxcli software vib remove --vibname scsi-qla2xxx
esxcli software vib remove --vibname scsi-lpfc820
Just putting this out here in case someone else is running into this - haven't seen any other posts referencing it, but TAC says that several customers are running into this same problem.
