The reason Android is one of the most loved operating systems in the world is the flexibility it offers. It can either be used out of the box for normal users, or enthusiasts can tinker and make the device their own in unlimited ways.
On XDA Forums, according to senior developer dreinulldrei, modifying your an ini file theoretically increases the WiFi speed of the OnePlus 3/3T, but only under certain circumstances. By default, channel bonding is disabled for 2.4GHz frequency. 5GHz frequency has channel bonding enabled by default, but it’s not eh the same case for the latter. Channel bonding increases the channel width from 20MHz to 40MHz. This should theoretically double your bandwidth and work under certain conditions.
Note that you require root access to enable channel bonding on 2.5GHz.
All it takes is to edit a line in the WCNSS_qcom_cfg.ini file. This is located at /system/etc/wifi. You can browse to this folder using your file explorer of choice, we recommend using Root Explorer. Change the line gChannelBondingMode24GHz=0 to gChannelBondingMode24GHz=1. That’s it.
There is a good reason why OnePlus did not enable this feature by default. The possibility of wireless interference goes up. The 2.4GHz is divided into different bands to avoid interference, and what channel bonding does is basically use multiple bands to theoretically improve performance. This can cause the opposite, resulting in more interference in urban areas, where WiFi access points are aplenty. If you’re living in an area with not many WiFi routers around, then this trick might just work for you.
Let us know in the comment section if this tweak worked for you.