Once you install the beta firmware you can find the band selection option under Basic --> Internet 

@john.awad Good point... Caught me out also ;)

Hello,

Thank for the link.

For work you need to select only Band A and to put Band B at None, save and after return to band selection and select the Band B.

After reboot, need to do the same handling.

@Kladz Makes no difference for me - Bands 3 and 20 on ee selected, the settings still say 3,3...

Still working well (without the Omni Antenna too)

@darant 

Lovely, thanks for sharing!
Any idea if it's possible to revert back to the latest standard firmware after upgrading or if the router blocks downgrades?

@darant oh yeah thx

@darant 

Now it is working perfect

For me B3+B28👌

Thanks a lot TP Link

Witch this new feature this router is best than Huawei !

@jrferreira No idea, why would anyone ;)

@darant 

Because beta software is beta for a reason ;)