diff --git a/docker/rootfs/etc/s6-overlay/s6-rc.d/prepare/50-ipv6.sh b/docker/rootfs/etc/s6-overlay/s6-rc.d/prepare/50-ipv6.sh
index 76e9a651..0c4d261c 100755
--- a/docker/rootfs/etc/s6-overlay/s6-rc.d/prepare/50-ipv6.sh
+++ b/docker/rootfs/etc/s6-overlay/s6-rc.d/prepare/50-ipv6.sh
@@ -28,7 +28,7 @@ process_folder () {
 	for FILE in $FILES
 	do
 		echo "- ${FILE}"
-		sed -E -i "$SED_REGEX" "$FILE"
+		echo "$(sed -E "$SED_REGEX" "$FILE")" > $FILE
 	done
 
 	# ensure the files are still owned by the npm user