FAT32にはなってる
$ sudo sfdisk --list /dev/sda
Disk /dev/sda: 57.3 GiB, 61524148224 bytes, 120164352 sectors
Disk model: SanDisk 3.2Gen1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000
Device Boot Start End Sectors Size Id Type
/dev/sda1 32 120164351 120164320 57.3G c W95 FAT32 (LBA)