diff --git a/build.sh b/build.sh
index 6db2402..4147485 100755
--- a/build.sh
+++ b/build.sh
@@ -2,6 +2,9 @@
 
 set -euxo pipefail
 
+echo 'permission test' > /mnt/alpine/test
+rm /mnt/alpine/test
+
 for repo in sakamoto; do
 	for pkg in $repo/*; do
 		cd $pkg