diff --git a/prepare-image/seco-hmi-postinstallation.sh b/prepare-image/seco-hmi-postinstallation.sh
index f05608754a2a48209e2031f69f9d8dfbfaa8aedb..46523a4adfbb5ab95b1c876cbfca3d78dcc03329 100644
--- a/prepare-image/seco-hmi-postinstallation.sh
+++ b/prepare-image/seco-hmi-postinstallation.sh
@@ -8,28 +8,30 @@ OVERLAY_FILE="gfxml-overlay.dtbo"
 umount -q $SHARED_MOUNT
 umount -q $BOOT_MOUNT
 
+printf "Create mount points and partitions\n"
+
 rootfs_dev=$(findmnt -n -o SOURCE /)
-prefix=$(echo $rootfs_dev | grep -o -e .*p)
-rootfs_part_num=$(echo ${rootfs_dev: -1})
-bootfs_part_num=`expr $rootfs_part_num - 1`
+rootfs_part_num="${rootfs_dev##*p}"
+prefix="${rootfs_dev%$rootfs_part_num}"
+bootfs_part_num=$((rootfs_part_num - 1))
 bootfs_dev=$prefix$bootfs_part_num
 
 mkdir -p $SHARED_MOUNT
 mkdir -p $BOOT_MOUNT
 mount $SHARED_PART $SHARED_MOUNT
-mount $bootfs_dev $BOOT_MOUNT
+mount "$bootfs_dev" $BOOT_MOUNT
 
 if ! test -f $BOOT_MOUNT/$OVERLAY_FILE
 then
-    FSL=""
-    if grep -q -i mxcfb $BOOT_MOUNT/*.dtb
-    then
-        FSL="--fsl"
-    fi
+    printf "Run post-install scripts ...\n"
 
     export BOOTPARTITION="$bootfs_dev"
     fnginstall-postinstallation
+else
+    printf "Overlay already exists\n"
 fi
 
+printf "Finished\n"
+
 umount $SHARED_MOUNT
 umount $BOOT_MOUNT