Re: vfat on Linux, any UEFI system has a vfat EFI System partition, so it might be useful to check for this file system.
Re: The first sector, a.k.a. VBR (volume boot record or volume boot sector) might validly be non-zero as non-UEFI bootloaders can write to this location.
Re: The first sector, a.k.a. VBR (volume boot record or volume boot sector) might validly be non-zero as non-UEFI bootloaders can write to this location.