I have same issue with my archer c60 its turns off itself and turn on like we did a poweroff and on of router... 1 thing I noticed that this happens when i connect any device with its 5ghz band wifi...

@Solla-topee I also have same problem with Archer c6 (EU) ver2.0 I tried firmware update also but didn't work I also tried not to connect any device in wifi but same issue at there... Please help I...