In the latest version of grub-mkimage, the prefix option is mandatory.
Not supplying it fails with:
```
Prefix not specified (use the -p option).
```
In grub-2.02-beta2 a DEFAULT_DIRECTORY was defined
in `include/grub/osdep/hostfile_unix.h` as:
```
#if defined (__NetBSD__)
/* NetBSD uses /boot for its boot block. */
# define DEFAULT_DIRECTORY "/"GRUB_DIR_NAME
#else
# define DEFAULT_DIRECTORY "/"GRUB_BOOT_DIR_NAME"/"GRUB_DIR_NAME
#endif
```
Where:
* GRUB_BOOT_DIR_NAME == boot
* GRUB_DIR_NAME == grub
This was used if the -p option was omitted.
Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Alexandru Ardelean
81a2f9d6f8