How does a homeless child living on the streets of Zaun with no access to a lab or expensive materials create a device like the Z drive? 
-Edit- sorry, haven't really actually read his lore. I now understand he is not homeless thank you for the replies, but the question still remains. xD
Well, we have 13 and 14 year olds in our world who build nuclear fusion reactors in their parents sheds and garages. So with (as GreenLore and Legacy of Xion have mentioned) the advantage of having a home and well-meaning parents, it seems highly impressive, but not impossible, that a kid like Ekko could make something amazing using the bits and parts that could be found in Zaun.
Apparently Ekko's parents are still alive and well, not gone or dead. Just always, always busy.
Yes, Ekko is not homeless or poor. Enjoy that plothole
Ekko still has parents and is probably a teen genius.
Aside from that he might have had learned some stuff from someone else in one way or another. For example what if he found one of zileans inventions,analyzed it and uses the knowledge that he gained by analyzing this machine to create the Z-Drive?
He didn't.
The Z drive was the prize in his cereal box.
Oh, nothing was explained in the new lore about him? Im schocked! (sarcasm)
New head-cannon: Ekko went back in time and gave his younger self the Z-Drive, making it's existence an Ontological Paradox. He's still a genius because he took that and reverse engineered it so he can repair it when necessary, but the first Z-Drive came from nowhere. Or nowhen? 
in the Ekko Q&A, they explain that Ekko isn't homeless and he's not an orphan. He just stays out on the streets more often because his parents are never around.
Homeless? You might want to read up a bit on Ekko.
Another reason why Riot should actually add lore.
He's the Bill Gates of Zaun.
