Palette 3 won't update via USB

So I’m just trying to get my Palette 3 Pro running. It automatically updated to the latest firmware on setup, BUT I was going to use it with my Prusa I3 Mk3s+. Thankfully an acquaintance informed me that I needed the Alternate firmware before I set out printing, however I cannot seem to update the firmware. I load the Alternate firmware zip contents onto the USB stick, plug it into the P3P, enter the Firmware->Update via USB, and nothing is there. The P3P isn’t seeing anything on the USB stick. I put the stick in two different computers, wiped it clean and reloaded it. I tried restarting the P3P, connecting to each USB port on it, and nothing is working. It just says there is nothing found on the USB stick every time I open up the menu.

Am I missing something? I tried shuffling the zip contents and just dumping them into the main stick directory, that didn’t do anything. The firmware update instructions make it seem like this is all I should have had to do…