diff --git a/setup.sh b/setup.sh
index 2a3bcec..fe79a5d 100755
--- a/setup.sh
+++ b/setup.sh
@@ -25,12 +25,12 @@ unset root_pwd
 chroot=/mnt/root-unlocked
 
 # root device
-mkfs.btrfs /dev/mapper/root-unlocked
+mkfs.btrfs -f /dev/mapper/root-unlocked
 mkdir /mnt/root-unlocked
 mount /dev/mapper/root-unlocked /mnt/root-unlocked
 
 # boot device
-mkfs.btrfs "$boot"
+mkfs.btrfs -f "$boot"
 mkdir "$chroot/boot"
 mount "$boot" "$chroot/boot"