Symptom

Fail to upgrade a Firepower NGIPS device from version 6.2.3.12 to version 6.4.0

Conditions

The Firepower NGIPS device to be upgraded has been downgraded from 6.2.3.12 and upgraded to 6.2.3.12 again previously.

Workaround

Run the following command in expert mode root shell before performing upgrade: rm -f /boot/kernels/*

Further Problem Description