For mine, the metal cover over connections to the main-board (from step 14) was hooked on the left side to the main-board and had to slide it to left to remove it. For which I had to first remove the "Nvidia NB106-N baseband module" from step 11 before I could remove the metal cover. Also, all the connections were covered with sticky tape and required extra caution not to damage the connections.
My tango dev-kit tablet fell from a height of about one meter. The screen failed and did not display anything. It did power the screen (backlight) and the touch worked. But the screen was black and did not display anything.
I was hoping that the damage was not substantial, something like a connection problem. I opened the tablet following the revertible steps in this instruction. Assembled again and now it's working! This was really exciting , thank you so much :)