If you have encountered an issue whereby your firmware has not updated because of a failure to verify the signature, it is likely that you are running old firmware.
This issue is encountered if you are running firmware 5.1.93 on the Ultimaker S5, and firmware 4.3.96 on the Ultimaker 3.
There is a software bug which prevents the firmware versions above to update if the printer does not have the correct timestamp set.
Note: The above firmware versions are meant as stepping stone firmware. It is important to update to the latest stable as soon as possible.
The simplest way to resolve this error is by connecting your printer to the internet:
- Via ethernet
- Via Wi-Fi to a local network
- Via Wi-Fi to a mobile hotspot
Once the printer is connected, it will update its timestamp. With an updated timestamp the printer will be able to verify the signature of new update packages, and will update itself via USB or network.