diff --git a/scripts/firstrun b/scripts/firstrun
index 4ac34019fd..6ebf4c5588 100644
--- a/scripts/firstrun
+++ b/scripts/firstrun
@@ -26,8 +26,8 @@ set -e
 do_expand_rootfs(){
         device="/dev/"$(lsblk -idn -o NAME | grep mmcblk0)
 		PARTITIONS=$(($(fdisk -l $device | grep $device | wc -l)-1))
-		PARTSTART=$(parted $LOOP unit s print -sm | tail -1 | cut -d: -f2 | sed 's/s//') # start of first partition
-		PARTEND=$(parted $LOOP unit s print -sm | head -3 | tail -1 | cut -d: -f3 | sed 's/s//') # end of first partition
+		PARTSTART=$(parted $device unit s print -sm | tail -1 | cut -d: -f2 | sed 's/s//') # start of first partition
+		PARTEND=$(parted $device unit s print -sm | head -3 | tail -1 | cut -d: -f3 | sed 's/s//') # end of first partition
 		STARTFROM=$(($PARTEND+1))
 		[[ $PARTITIONS == 1 ]] && STARTFROM=$PARTSTART
 		((echo d; echo $PARTITIONS; echo n; echo p; echo ; echo $STARTFROM; echo ; echo w;) | fdisk $device)>/dev/null