I think /boot/efi is mounted on my system as shown by lsblk so I'm not sure why I got this error.
$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 931.5G 0 disk ├─sda1 8:1 0 128M 0 part ├─sda2 8:2 0 1000M 0 part ├─sda3 8:3 0 260M 0 part /boot/efi ├─sda4 8:4 0 500M 0 part ├─sda5 8:5 0 418.4G 0 part /media/tom/Windows8_OS ├─sda6 8:6 0 2G 0 part [SWAP] └─sda7 8:7 0 296.1G 0 part / sdd 8:48 1 3.7G 0 disk └─sdd1 8:49 1 3.7G 0 part
I think /boot/efi is mounted on my system as shown by lsblk so I'm not sure why I got this error.
$ lsblk tom/Windows8_ OS
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 931.5G 0 disk
├─sda1 8:1 0 128M 0 part
├─sda2 8:2 0 1000M 0 part
├─sda3 8:3 0 260M 0 part /boot/efi
├─sda4 8:4 0 500M 0 part
├─sda5 8:5 0 418.4G 0 part /media/
├─sda6 8:6 0 2G 0 part [SWAP]
└─sda7 8:7 0 296.1G 0 part /
sdd 8:48 1 3.7G 0 disk
└─sdd1 8:49 1 3.7G 0 part