$ sudo grub-probe -v -t partmap /dev/sda 2>&1 | grep error
grub-probe: error: failed to get canonical path of `udev'.

$ sudo grub-probe -v -t partmap /dev/sdb 2>&1 | grep error
grub-probe: error: failed to get canonical path of `udev'.



### And another nonsense:

$ sudo grub-probe -v --target=partmap -d /dev/sda 2>&1 | grep partition
grub-probe: info: no partition map found for hd1.


$ sudo grub-probe -v --target=partmap -d /dev/sdb 2>&1 | grep partition
grub-probe: info: no partition map found for hd0.



### And the last one (This one is already recognized as confirmed bug in Ubuntu):

$ sudo grub-probe -v --target=partmap -d /dev/sdb5 2>&1 | grep partition
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd1).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd2).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd4).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd5).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd6).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd7).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd8).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd10).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd11).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd12).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd13).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd14).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd15).

# But sdb1 has no BSD-Disklabel. Nonetheless:
$ sudo grub-probe -v --target=partmap -d /dev/sdb1 2>&1 | grep partition
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd1).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd2).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd4).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd5).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd6).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd7).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd8).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd10).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd11).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd12).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd13).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd14).
grub-probe: warning: Discarding improperly nested partition (hd0,gpt5,bsd15).