2.5 Upgrade to 2.6 on CSS106 does not work

I have a few CSS106-5G-1S switches. All of these I have been able to upgrade from 2.5 to 2.6 except for one.

I’m following the release notes to upgrade from the 2.6 downloaded bits - then wait for some time and reboot. I have tried many times and have waited for a long time before the reboot - nothing seems to work.

Anyone else having these issues?

Thanks,

Rich