I have the MSI Creator P50 and I'm trying to flash the BIOS, but the M-FLASH UI never sees any files on my USB drive. It sees the drive (with the correct name), it sees the folders on the drive, and I can navigate down and up through the folders. But it never sees any files, even though I unzipped the BIOS upgrade file to the root of the drive. I've tried 3 different USB drives and they all behave this way. What am I doing wrong?