Procedure

  1. Start with an empty (unpartitioned, unformatted) SD card. If you disk is not empty, you will need to do a search on how to clean the disk and create an msdos disklabel (aka partition table).

    Gnome Disks showing an empty, unpartitioned SD cardGnome Disks showing an empty, unpartitioned SD card

  2. Add boot partition Gnome Disks while adding a primary partitionGnome Disks while adding a primary partition

  3. Format as VFAT (part of partition-creation wizard) Gnome Disks add parition wizard format as vfatGnome Disks add parition wizard format as vfat

  4. Result is a partition formatted as FAT 16 Gnome Disks showing SD card with FAT 16 boot partitionGnome Disks showing SD card with FAT 16 boot partition

  5. Make the partition bootable Gnome Disks setting partition as bootableGnome Disks setting partition as bootable

  6. We want FAT 32 so use terminal to reformat as FAT 32 Drop to terminal to reformat as FAT 32 because GNOME disks doesn’t have that optionDrop to terminal to reformat as FAT 32 because GNOME disks doesn’t have that option

  7. Resulting FAT 32 formatted boot partition Gnome Disks showing boot parition formatted as FAT 32Gnome Disks showing boot parition formatted as FAT 32

  8. Mount the boot partition for next steps Gnome Disks showing boot partition mountedGnome Disks showing boot partition mounted