@Marcelo-Alegria When the Smart Connection is enabled on the AX6000, it will automatically broadcast a 5G signal at band 4, which could be 140 as you already found, so the RE505X cannot see it. The...

@m4rk_ Yes, there should be an official release in the future, while we cannot provide an ETA yet.

@RockPaper May I know the reason why you want to downgrade? This new 1.2.1 cannot be rolled back, while we will try to work it out if you are experiencing an issue.

@Rosi46 If you are looking for the beta firmware to select the band manually, please refer to this thread: https://community.tp-link.com/en/home/forum/topic/241534

@Sledger17 Yes, the US version should be compatible with band 4.

@Luca21 You can find it here as per the router version: https://community.tp-link.com/en/home/forum/topic/241534