I am using a Deco M9 Plus system with 4 units. Yesterday I reinstalled all the units and 3 of the 4 unit updated the firmware to the latest version 1.5.6 . 1 unit is not doing this, and when I connect it to the others it keeps showing that the whole network is on v1.2 and that this is ok.

The unit does connect to the network and the cable connected NAS server on this unit is accessible over the network. However the unit does not work as a mesh router for other clients.

Is there a way to force the upgrade on this single unit without causing problems on the 3 units that are working fine?

Thanks in advance,