diff --git a/usr/lib/archboot/installer/partition.sh b/usr/lib/archboot/installer/partition.sh
index 447f09048..d6a0eea6c 100644
--- a/usr/lib/archboot/installer/partition.sh
+++ b/usr/lib/archboot/installer/partition.sh
@@ -3,7 +3,7 @@
 # created by Tobias Powalowski <tpowa@archlinux.org>
 _check_gpt() {
     _GUID_DETECTED=""
-    [[ "$(${_LSBLK} PTTYPE "${_DISK}")" == "gpt" ]] && _GUID_DETECTED=1
+    [[ "$(${_LSBLK} PTTYPE -d "${_DISK}")" == "gpt" ]] && _GUID_DETECTED=1
     if [[ -z "${_GUID_DETECTED}" ]]; then
         _dialog --defaultno --yesno "Setup detected no GUID (gpt) partition table on ${_DISK}.\n\nDo you want to create a new GUID (gpt) table now on ${_DISK}?\n\n${_DISK} will be COMPLETELY ERASED!  Are you absolutely sure?" 0 0 || return 1
         _clean_disk "${_DISK}"
@@ -56,7 +56,7 @@ _partition() {
                 _RUN_CFDISK=1
                 _check_gpt
             else
-                [[ "$(${_LSBLK} PTTYPE "${_DISK}")" == "dos" ]] && _MSDOS_DETECTED=1
+                [[ "$(${_LSBLK} PTTYPE -d "${_DISK}")" == "dos" ]] && _MSDOS_DETECTED=1
                 if [[ -z "${_MSDOS_DETECTED}" ]]; then
                     _dialog --defaultno --yesno "Setup detected no MBR/BIOS partition table on ${_DISK}.\nDo you want to create a MBR/BIOS partition table now on ${_DISK}?\n\n${_DISK} will be COMPLETELY ERASED!  Are you absolutely sure?" 0 0 || return 1
                     _clean_disk "${_DISK}"