Nice. Well done. Just an idea, but maybe you could make a rotation of your screen to have it in face with a rotation 0 to avoid to change all codes ?
It’s maybe too late but i think it’s could be easier to change it now than to make all needed to have your own app store. Else Roman have put source online for the client here: https://github.com/ESPboy-edu/ESPboy_OTA but i don’t think that server configuration is explained somewhere (maybe i just missed it).
Welcome and have fun 
2 Likes