Troubleshooting Tip: FortiGate fails to boot after attempting an upgrade from 7.2.13 to 7.4.11 - Stuck in "initializing firewall"

Description

This article describes the issue of being unable to upgrade FortiGate from v7.2.13 to v7.4.11. The user is experiencing a boot failure after attempting to upgrade the FortiGate device. It is stuck in 'initializing firewall'.

Scope

FortiOS v7.2 and v7.4.

Solution

Verification steps:

1. Connect a console cable before proceeding to the upgrade. This issue is only possible to verify from the FortiGate console.

2. After the power cycle, the upgrade is stuck here:
   
   

FTG120G#
Image verification OK!

Firmware upgrade in progress ...
Done.

The system is going down NOW !!

Please stand by while rebooting the system.
Restarting system

FortiGate-120G (01:29-11.09.2023)
Ver:06000104
Serial number: FG120GTKXXXXXXXX
CPU: 2300 MHz
Total RAM: 8 GB
Initializing boot device...
Initializing MAC...
Please wait for OS to boot, or press any key to display configuration menu......

Booting OS...
Initializing firewall...

System is starting...

Explanation:

On v7.2.13, CLI should not allow config system interface entry of set type switch unless there is a corresponding config system switch-interface: config system interface.

Example: 2 objects with interface type switch:

config system interface
    edit "interface 1"
        set vdom "root"
        set allowaccess ping https ssh
        set type switch
        set device-identification enable
        set role lan
        set snmp-index 35
    next
    edit "interface 2"
        set vdom "root"
        set allowaccess ping https ssh
        set type switch
        set device-identification enable
        set role lan
        set snmp-index 25
    next
end

However, there are no members configured for interface 2:

config system switch-interface
    edit "interface 1"
        set vdom "root"
        set member "port1" "port2"
    next
end

Solution:

To resolve the issue of being unable to upgrade FortiGate from v7.2.13 to v7.4.11, follow these steps:

1. Back up the current configuration.

2. Open the configuration file and locate the object under the config system interfaces section.

3. Remove the object from the configuration, as it is an unused interface configured as a switch type without member interfaces.

4. Restore the edited configuration file to FortiGate.

5. Reboot the system to apply the changes.

6. Proceed with upgrading to the desired FortiOS version.