@Steve-Hobley It's a Nano clone so the chips have been replaced with Chinese equivalents, but it works the same... except less reliably. Arduino IDE works to program them, just tell it you have a Nano.
Yes, I use OptiBoot. You can load it with a Uno using the ICSP connector or with a programmer (they only cost a couple of bucks).
It's been a while but even with OptiBoot I couldn't get CoreXY to fit with the homing and other stuff I usually use so you have to pair it down some. That's probably why Eleks stuck with 0.9i, but Grbl 1.1 has some nice features and faster / smoother motion which I prefer.