FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 247112
Description This article explains how to solve the 'Installed firmware is not signed by Fortinet' error.
Scope FortiGate
Solution iskandar_lie_0-1677247108286.png


This screen may appear when accessing FortiGate through HTTPS. The CLI will show a similar warning. It can happen on any FortiOS version after performing an upgrade.  


A system status check of the CLI shows the firmware is un-certified: 


FGT # get system status
Version: FortiGate-VM64-AZURE v7.0.9,build0444,221121 (GA.M)
Firmware Signature: un-certified
Virus-DB: 1.00000(2018-04-09 18:07)


This happens when an image verification fails during image upgrade and is cached. 


This warning can be left as-is until the next upgrade. It will not affect performance or device operations.

To resolve the issue, re-flash the affected device. Manually download and verify the OS image from this page:


Relevant documentation:

Technical Tip: How to upgrade the FortiGate firmwa... - Fortinet Community

Technical Tip: FortiGate HA upgrade procedure and ... - Fortinet Community

Technical Tip: Rebuilding an HA cluster

Technical Tip: Installing firmware from system reboot

FortiOS image signing and verification