In order to carry out ISSU upgrade to a Dual Sup 8 card in 4510, the configuration register will need to be in 0x2102 to begin with. I have changed the configuration register from default 0x2101 to 0x2102 (never reboot).Then, we performed and upgrade...

Just to check does this applies to 4510 with Dual Sup 8 module card? If both 4510 Sup 8 module card is in 0x2101 and forced to 0x2102, then an upgrade was carry out to the firmware. All the links go down after the upgrade.