Last week I received my Raspi Boy. I'm very happy with it.
But just one day after I assembled it, Retropie released the 4.3 update.
So, I had to disassemble again to change the image os micro SD...

Then I had the idea to put a memory card slot to get external access to micro Sd.
And works!

I did it with two different micro SD extension cable, those for GPS and players for cars with hidden memory slot.
Using two cables at once you expect to not work properly, but I have not failures yet.
The result is better than expected.
I did a tutorial, for anyone how want to do it.
Whose with 6000mAh battery maybe can't do the mod because there is no space enough inside the Raspi Boy.
https://www.youtube.com/watch?v=S1KpB-ejikk