When you upgrade from a Pre-08.0.90 Non-UFI image Version to 08.0.90 UFI image Version or newer versions, you might encounter a boot-monitor version mismatch error message. The show version command might also display a boot code mismatch message after performing the software upgrade.
(snippet of the error message):
show boot-monitor command displays:
To fix this issue, re-copy the UFI image of the code you are installing to the primary and the secondary flash partition to avoid boot image mismatch.
(In this example, 8090m UFI was already installed on primary partition, so it's now being copied to secondary partition to fix the issue).