Prepare SD card using GNOME Disks
Procedure
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).Add boot partition
Format as VFAT (part of partition-creation wizard)
Result is a partition formatted as FAT 16
Make the partition bootable
We want FAT 32 so use terminal to reformat as FAT 32
Resulting FAT 32 formatted boot partition
Mount the boot partition for next steps