One of our techs just updated the firmware successfully using an 8GB card and a 32GB card, both formatted to FAT32. The cards were blank except for the "sd_vico_MS3.bin" file.
One issue was that the camera asked numerous times to format the card, so if that happens, make sure you hit cancel, and take it slow so that you don't miss those prompts if they pop up.
The second thing worth mentioning is that it's a bit temperamental when accepting the button combination. After entering playback mode, the instructions say to press and hold the orange button and the up button simultaneously for a few seconds.
We had to press the orange button first, and then a half second later, press the the up button, and held both for almost 10 seconds before the camera recognized the button combination and started to update.