I made FW foy joyetech (Wismec/eleaf) devices with big Screen (like RX Gen 3).
It's based on MyEvic and Sur_MyEvic project and support a lot of features, interface and usability improvements (like light stealth mode).
Also, it's fully open and everyone can make some suggestion/build the FW for youself.
My FW has always up-to-date online installer - you just need to press "update" button
like, but you can always any offline flasher
I will write more about it, if it will be interesting for you
It's based on MyEvic and Sur_MyEvic project and support a lot of features, interface and usability improvements (like light stealth mode).
Also, it's fully open and everyone can make some suggestion/build the FW for youself.

My FW has always up-to-date online installer - you just need to press "update" button
like, but you can always any offline flasher
I will write more about it, if it will be interesting for you