Onion sent me a new OLED, and I'm happy to report that it is working just fine. I didn't change anything else.
If I get time, I'll try to debug whats wrong with the original one. Suggestions welcome.
I did notice that when with the new OLED, when I do
% oled-exp -v
So the value changed from 0xff to 0x03. Not sure if that matters.
Thanks to everyone who tried to help out. Appreciate that.