Add "New device" button at the end

[MagicLike]

For people who flash multiple devices at once it would be handy to have a button to start over at the end.

[MagicLike]

@tsterbak I am currently adding the button to restart. I want it to show the StartView, but I get this error: AttributeError: 'MainView' object has no attribute 'StartView'. Where should I add the attribute? (I have never properly worked with Python before + I only know the half of how OAI works 😅)

Edit: solved

[MagicLike]

@tsterbak I will commit my current changes, but it has bugs which I am not able to fix. Please be so kind and have a look over it / test it.

Commit: 13c3500

[tsterbak]

Thank you! I'll look at it and fix it :)

[MagicLike]

Now continued in #123 #163