Best Of

one hint we got was (not sure if it was for the N2400 series, but...)
reboot the Encoders and decoder before the update, then after they are back, immediately do the fw update.

And I found the following notes in our fw archive:

• Firmware on the device older than 1.4.6 will need to be upgraded to 1.4.7 first before proceeding to upgrade the 1.5.x firmware.

• Firmware on the device older than 1.5.81 will need to be upgraded to 1.5.82 first before
  proceeding to upgrade the 1.5.113 or greater firmware.

• When upgrading to 1.5.113 or greater, the upgrade time is longer than usual. The upgrade time is about 10-12 minutes per device. Please wait for the device to reboot to confirm update

@marco_miano
Here's the 1.5.114: https://cloud.audiogroup.org/index.php/s/gW6NArgMJwsNHX3
Let me know when you got it.