diff --git a/misc/factor.sh b/misc/factor.sh
index b96aa8d24b..276956b0b7 100755
--- a/misc/factor.sh
+++ b/misc/factor.sh
@@ -306,7 +306,10 @@ update_boot_images() {
         get_url http://factorcode.org/images/latest/checksums.txt
         factorcode_md5=`cat checksums.txt|grep $BOOT_IMAGE|cut -f2 -d' '`;
         set_md5sum
-        disk_md5=`$MD5SUM $BOOT_IMAGE|cut -f1 -d' '`;
+        case $OS in
+             netbsd) disk_md5=`md5 $BOOT_IMAGE | cut -f4 -d' '`;;
+             *) disk_md5=`$MD5SUM $BOOT_IMAGE|cut -f1 -d' '` ;;
+        esac
         echo "Factorcode md5: $factorcode_md5";
         echo "Disk md5: $disk_md5";
         if [[ "$factorcode_md5" == "$disk_md5" ]] ; then