11. Can I flash a different stock firmware on my device? ie flash Android One on Retail or another variant

12. I am rooted and now Official OTAs don't install

13. What the hect is this A/B partition stuff people keep mentioning?

14. Best camera to use?

15. I'm not on Retail version, how can I enable One Button Nav?

Yes. Non-US variant users have reported successful flashes of US firmwares in this thread . Ensure you have a TWRP backup before performing just in case.This is a known issue with no fix. Your only option is to wait for copy of latest firmware to be available and manually flash it without theto keep your data ( customized script here ). Another option is if you are receiving the OTA notification, manually re-flash current firmware build without theto keep your data and proceed to accept the OTA (You will have to re-install TWRP/re-root.)Great XDA article will best explain it all.When you boot into TWRP, where it shows that active slot, remember when you do a flash you flash to the other slot. Example: If you're on A, you will flash to slot B and vice versa. Yes you can have stock firmware on one and a custom ROM on another but they share the same data partition. So its notin the way you're thinking.Refer to this XDA Thread by @ uccollab and this reddit thread.For Oreo - TBDFor Pie - Post by @ jhedfors - Need root