diff --git a/hooks/file-mirror-automount/setup00.sh b/hooks/file-mirror-automount/setup00.sh
index 354b661..61f60f2 100755
--- a/hooks/file-mirror-automount/setup00.sh
+++ b/hooks/file-mirror-automount/setup00.sh
@@ -14,6 +14,10 @@ env APT_CONFIG="$MMDEBSTRAP_APT_CONFIG" apt-get indextargets --no-release-info -
 	| sort -u \
 	| while read -r path; do
 		mkdir -p "$rootdir/run/mmdebstrap"
+		if [ ! -d "/$path" ]; then
+			echo "/$path is not an existing directory" >&2
+			continue
+		fi
 		case $MMDEBSTRAP_MODE in
 			root|unshare)
 				echo "bind-mounting /$path into the chroot" >&2
@@ -22,8 +26,8 @@ env APT_CONFIG="$MMDEBSTRAP_APT_CONFIG" apt-get indextargets --no-release-info -
 				;;
 			*)
 				echo "copying /$path into the chroot" >&2
-				mkdir -p "$rootdir/$(dirname "$path")"
-				cp -av "/$path" "$rootdir/$(dirname "$path")"
+				mkdir -p "$rootdir/$path"
+				"$MMDEBSTRAP_ARGV0" --hook-helper "$rootdir" "$MMDEBSTRAP_MODE" "$MMDEBSTRAP_HOOK" env "$MMDEBSTRAP_VERBOSITY" sync-in "/$path" "/$path" <&"$MMDEBSTRAP_HOOKSOCK" >&"$MMDEBSTRAP_HOOKSOCK"
 				;;
 		esac
 		printf '/%s\0' "$path" >> "$rootdir/run/mmdebstrap/file-mirror-automount"
@@ -47,6 +51,10 @@ for pkg in $MMDEBSTRAP_INCLUDE; do
 	fi
 	# make path absolute
 	pkg="$(realpath "$pkg")"
+	case "$pkg" in
+		/*) : ;;
+		*) echo "path for $pkg is not absolute" >&2; continue;;
+	esac
 	mkdir -p "$rootdir/run/mmdebstrap"
 	mkdir -p "$rootdir/$(dirname "$pkg")"
 	case $MMDEBSTRAP_MODE in
@@ -57,7 +65,7 @@ for pkg in $MMDEBSTRAP_INCLUDE; do
 			;;
 		*)
 			echo "copying $pkg into the chroot" >&2
-			cp -av "$pkg" "$rootdir/$pkg"
+			"$MMDEBSTRAP_ARGV0" --hook-helper "$rootdir" "$MMDEBSTRAP_MODE" "$MMDEBSTRAP_HOOK" env "$MMDEBSTRAP_VERBOSITY" upload "$pkg" "$pkg" <&"$MMDEBSTRAP_HOOKSOCK" >&"$MMDEBSTRAP_HOOKSOCK"
 			;;
 	esac
 	printf '/%s\0' "$pkg" >> "$rootdir/run/mmdebstrap/file-mirror-automount"