1. The current network topology/diagram. Modem - Deco M5 (Router Mode) - 2-Slave Deco 2. The model number of the Deco and the light status when the connection drops out/ Deco M5, All Deco's lights...

I got a absoultely same issue as janoosti after upgrading to 1.2.8. (and I also have M5 V1) I also want to return to 1.2.4 which didn't make any issue.