diff --git a/Dockerfile b/Dockerfile
index 6c402f8..b1351d4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,8 @@
 FROM archlinux:base-devel
 
+ADD rootca.pem /root
+RUN trust anchor /root/rootca.pem && update-ca-trust
+
 RUN cat > /etc/pacman.d/mirrorlist <<'EOF'
 Server = https://archlinux.cs.nycu.edu.tw/$repo/os/$arch
 EOF
@@ -13,9 +16,6 @@ EOF
 RUN pacman-key --init && pacman-key --populate
 RUN pacman -Syu --needed --noconfirm nodejs minio-client git
 
-ADD rootca.pem /root
-RUN trust anchor /root/rootca.pem && update-ca-trust
-
 RUN echo '%wheel ALL=(ALL:ALL) NOPASSWD: ALL' >> /etc/sudoers
 RUN useradd -mG wheel -d /build builder