Boot loop after screen replacement

I have a friend's iPhone 5c and I changed the screen out for a replacement. I have done this several times on different phones with great results. This time the phone displayed a few lines of [NAND] dialogue, with the message "s_cxt_boot:88 sftl: error, unclean shutdown; adopted 863 spans". I found a blog saying to try replacing the frontcam/sensor flexcable, and the frontcam/sensor connector at the mainboard. I have replaced the first part, but cant find any instructions to do the latter. I have another phone that works, and could simply put the new screen on the other phone, but she has never done any sort of icloud backup and doesn't want to lose her stuff. Can anyone direct me?