Technical Tip: FortiOS image signing and verification
Description
The BIOS checks the validity of an image when it is uploaded to the unit.
If the image is not signed by the Fortinet CA, a warning message is shown in the GUI.
Note:
Official FortiOS firmware images are signed by the Fortinet CA.
Scope
FortiGate.
Solution
Unsigned image.
Signed image
This happens when FortiGate cannot verify the image during the image upgrade and is cached.
This warning can be ignored until the next upgrade. It will not affect performance or device operations.
The possible solution is to reinstall the image or flash the FortiGate. Manually download and verify the OS image from this page:
