@Alexandre. So the problem is the app and not the firmware? THANK YOU so much! I already downgraded to 1.7.1 without solving, and I was about to recovery via TFTP and try 1.6.0 and 1.5.7 ( I found...

@David-TP I am not from Brazil, I am from Italy. Ho do I select my correct country in Deco or user?

@David-TP What is the last firmware with no secure option? I need to downgrade.

@kayyum_f388c764 I tried. Even guest network require a strong password. There is no more option for no secure. Deco M5 is now a useless product for me.

@David-TP I just find out 1.7.8 release for Deco M5 only accepts strong password for WiFi, even guest network! With an older version I was able to set weak password for regular network and even no...

In the new firmware release now Guest network must have a strong password, with letter, number, symbol, caps... Why on earth TP Link did that? Let the customer choose! It's totally useless for me...