Replaced top LCD, console doesn't turn on now (top screen flashes)

Yesterday, I spent quite a bit of time replacing the upper LCD on my DSi XL. However upon attempting to turn it on, the top screen flashed white and it immediately turned back off. From what I can find on Google, this means there's a problem with the bottom screen, but I can't find out what that is specifically (I have a couple of guesses though).

Powerwise it seems fine; It charges fine, or at least the orange charging LCD turns on, and it turns on (and then, well, off) on battery

My best guess it, when I was reassembling it, the clips for the Lower Backlight and (what I assume is) the Touchscreen Ribbon Cables broke off. I've tried taping them down but... is there a better alternative to sellotape? I assume Duct Tape or Electrical Tape or something. Assuming it would work at all.

Small Imgur album of the entire board and the two missing clips. Of course, it could be something else, too; I can't figure it out.