@Solla-topee 

Hi,

i finally managed to update the plug to the latest firmware 1.4.9 build 20210621 Rel. 30941

As you suggested in the mail, at first, i connected the plug in a local wifi hotspot created by an old android phone and then i opened the data to the internet so the plug and the tapo app could download/apply the update and... it succeeded!!!

So both plugs are now updated to the last firmware.

Thanks for the support.