@ckcampbell248 Update...I think I solved my own problem. I believe the problem is with the Notepad app in the demo firmware. We tried several different SD cards that were known to be working in M5Launcher and they all failed on two Cardputers using the demo firmware. I installed Launcher on my device, and I am able to install .bin files from the SD card.

@grimtechnet Did you ever solve this? I just got a new Cardputer and am experiencing the same result. I have tried two different 8GB cards formatted as FAT32 and also a 1GB card formatted as FAT and I get the same result with all of them. I tried both a quick format and a full format in Windows.