STBC (space-time block coding) is an optional feature in 802.11AC. It allows a transmitter to transmit multiple copies of data streams using a number of antennas. It also allows a receiver to select the best copy of data among those multiple copies to improve reliability. There is an inter-operability issue between Chromecast (2015) and Chromecast Audio and certain models of 802.11AC routers that use this feature on 5GHz Wi-fi. This could result in a slow download of the initial OTA (Over the Air Update).
If your router is on the list below, please factory reset your Chromecast or Chromecast Audio and re-setup on 2.4GHz Wi-Fi. Once setup is complete and the update is complete, you can switch back your Chromecast or Chromecast Audio to a 5GHz Wi-Fi network using the Google Home app.
- TPLink Archer C7 v1/v2
- Netgear R6100/6200/6300
- Asus RT_AC66U, RT_AC68W
- Buffalo WZR_D1800H