@Mathews123 

Mathews, 

I have X50 (BR) version, fabricated in Brazil, v.1.33

The lastest firmware on the website is 1.2.8 for 1.30, and no version for 1.33. however through the Deco app the firmware automatically updated to 1.2.10, just like yours.

My main Deco is X55 though, so all these features you listed only appreared in X55 beta software 1.6.4, thats where for the first time i noticed the Wi-Fi channel config. option.

I used 1.5.5 version (as for X50 US) on my Deco X50 (BR) and it was nothing special. So i retracted back  to 1.2.8 which was the atual one back then.

However to install 1.5.5 try initically restore your X50 to the basic firmware version, 1.2.2.

https://static.tp-link.com/upload/firmware/2023/202304/20230410/Deco_X50_1.0_1.2.2_Build_230301.zip

First you put Deco in restore mode, and then throuh restore interface upload the basic version, and afterwards, proceed to upgrade to 1.5.5. Use cable.

It worked for me, but like i said, my X50 works better with 1.2.10 software.

  @Mathews123 

Just saw that there is a newer version for Deco X5 US 1.6.1  available already with Wi-Fi channel configuration, however with no option to downgrade to previous one.

I think you may try it, and if you dont like you go through the same routine, restore it back to basics, and install your regional firmware.

In any case let me know how it goes, man.