diff --git a/lib/util-iso-aufs.sh b/lib/util-iso-aufs.sh
index a097095..4b0a977 100644
--- a/lib/util-iso-aufs.sh
+++ b/lib/util-iso-aufs.sh
@@ -11,12 +11,12 @@
 
 # $1: new branch
 mount_root_image(){
-	msg2 "mount [root-image] on [${1##*/}]"
+	msg2 "aufs: mount [root-image] on [${1##*/}]"
 	mount -t aufs -o br="$1":${work_dir}/root-image=ro none "$1"
 }
 
 mount_custom_image(){
-	msg2 "mount [${1##*/}] on [${custom}-image]"
+	msg2 "aufs: mount [${1##*/}] on [${custom}-image]"
 	mount -t aufs -o br="$1":${work_dir}/${custom}-image=ro:${work_dir}/root-image=ro none "$1"
 }
 
diff --git a/lib/util-iso-overlayfs.sh b/lib/util-iso-overlayfs.sh
index 314e97b..a57a2a0 100644
--- a/lib/util-iso-overlayfs.sh
+++ b/lib/util-iso-overlayfs.sh
@@ -11,13 +11,13 @@
 
 # $1: new branch
 mount_root_image(){
-	msg2 "mount [root-image] on [${1##*/}]"
+	msg2 "overlayfs: mount [root-image] on [${1##*/}]"
 	mkdir -p "${work_dir}/work"
 	mount -t overlay overlay -olowerdir="${work_dir}/root-image",upperdir="$1",workdir="${work_dir}/work" "$1"
 }
 
 mount_custom_image(){
-	msg2 "mount [${1##*/}] on [${custom}-image]"
+	msg2 "overlayfs: mount [${1##*/}] on [${custom}-image]"
 	mkdir -p "${work_dir}/work"
 	mount -t overlay overlay -olowerdir="${work_dir}/${custom}-image":"${work_dir}/root-image",upperdir="$1",workdir="${work_dir}/work" "$1"
 }