We have several ASA 5508's sitting in boxes for a couple years for a project that never started. We're repurposing them, but out of the box they are running 6.2.3. We've tried to 5 of them to 6.6.5, 6.5.0, and even 6.4.0. One went without a hitch to 6.5.0, although the upgrade process took 8 hours! Another seemed to upgrade OK but reverted back to 6.2.3. After looking at the logs, there didn't seem to be an error, so we're not sure why it reverted. The others just reboot and revert to 6.2.3. All upgrades are through FDM, the only changes made out of the box is the management IP, there were no backups configured, and there is plenty of disk space. I tried to upgrade two again last night, but after 1.75 hours, they hadn't attempted the reboot, and I couldn't log into them. When I came in this morning, they were back at 6.2.3.
Has anyone else experienced problems like this? Is there anything else we can try? Thanks
