Making your own mobile phone sounds like a daunting task, but it's actually really fun! We're not talking about a fancy iPhone here, but it is still quite an excellent learning experience.
Preparing for the steampunk apocalypse? You might want to make your own phone. This crowdfunded kit, fully funded, will take you from circuit board to code.
It's probably not a good idea to tear down and try to repair the hot new Samsung Galaxy Note 8 in the event of anything other than catastrophic damage.
Despite lacking a repairability score, this comprehensive OnePlus 5 teardown is far from encouraging for occasional smartphone handymen.
The Google Japanese Input Puchi Puchi Version isn't going to get mass produced, but you could get your hands into an Arduino board...