I think rooting is separate (but often part of) from putting on ROMs. xda-developers.com is usually the place to check, look at the forum for your device and they'll have guides plus links to various ROMs. It can be a lot to learn, sometimes they make tools that take a lot of the command line bits out for you. It's not completely without risk of bricking it.
I found the apk from that link a little earlier and have downloaded it, allowed installs from unknown locations and everything was looking positive - then I get a 'do you want to install this app'... and the install button does bog all. It doesn't seem clickable (or tapable). :C
So, is that symptomatic of the app not being able to be installed 'cos of reasons known only to Lego and what all sidelined apps do if they can't be installed, or is my tablet having a fit?
Edit - scrap that, I had a night mode filter in place that was stopping me clicking the install button. (fail)
It's installed, and the app opens up, then promptly closes itself down. Hmm, back to Lego support to see what they suggest.
I will try that, but first I've got to get another Pi3. My current one is far too well installed in a case, behind a screen and has all the cables nicely tided away to pull all that apart for some testing. :J
Hmm. Just downloaded it and installed it on my phone. It installed fine. Started, complained about the screen size, but I could say OK, then a splash screen came up, then it crashed/quit/closed
