@ryg You can download the Bangladesh firmware from the link below and then Unzip the Zip file and install it by Recovery Mode in Deco M4 by using your PC or Laptop. After the firmware successfully...

@ryg What's your 5 GHz wifi channel on Deco E4 ?? Can you please check on WiFi Analyzer App on phone. I think your Deco E4 units are supported channels 149 to 161 but your Deco M4 is'nt supported but...

@ryg i think u can install the Bangladesh beta firmware first which is so old 2022 or 2023 firmware then your M4 will provide you 5 GHz WiFi connection and then you can install the 1.6.5 stable...

@Marvin_S Don't u see that i set 45 Mbps and im still getting 50+ Mbps

@ryg You can use the Deco M4 as a (Main) unit and then try to install it

@ryg My all Deco M4 units are using 1.7.0 beta firmware i do the same steps which i guided you but i don't know why not working for you 😭😭