Right! I made that post last night from an iPad in a coffee shop, now I'm back home I can reveal all!What is the simpler way ?
The complex way uses something called Sunxi-Fel and Zadig. I imagine you'll find it by searching. I don't know if this method nets you more options but it looked too confusing to progress through. The easy method is called Hakchi2, this is the video I followed
Oh and because the NES Mini's control ports are just Wii controller extension ports, you can use the Classic Controller, Pro Controller, etc. I tried it with a GC controller (with Wii extension port rather than a USB or GC port) I bought for Smash Bros and it works too.
I wonder how far hackers can take this and if SNES or Gameboy games will be possible.