If there is a free space before the first partition, just ignore it. Use always the free space at the end of the disk.
Example of a disk with free space before the first partition:
Number Start End Size File system Name Flags
17.4kB 262kB 245kB Free Space
1 262kB 17.0MB 16.8MB fat16 legacy_boot
2 17.0MB 332MB 315MB
332MB 64.0GB 63.7GB Free Space
If there is a free space before the first partition, just ignore it. Use always the free space at the end of the disk.
Example of a disk with free space before the first partition:
Workaround for #492