Hey! you are making progress, that's good.

That happened to me once. The card reader was old. When I pulled it apart a contact had come undone. I soldered it up and it worked for awhile until another came undone so I purchased a new one.

Yeah, my card reader is in the box of the asus vivo pc very compact, I think its even on the MB, but I have to see if I can solve that in some way by bending a bit the card connection pins or something like that, because I notices that when I push up the card it gots recognized, if I leave it just inserted nothing happens, so probably only bending pins will solve that. But so far I am happy all with Banana is ok. I will then make a test install of the u-boot and see if I can get something on the screen session with the ttl cable.
After that all is easy.