diff --git a/full/Dockerfile b/full/Dockerfile
index 6ce778b..409bf55 100644
--- a/full/Dockerfile
+++ b/full/Dockerfile
@@ -1,8 +1,5 @@
 FROM znc:slim
 
-# I don't know what it should do. It works for me without this line, but not for @tianon
-USER root
-
 # znc:slim removed them. Install them again.
 RUN set -x \
     && apk add --no-cache \
@@ -12,6 +9,3 @@ RUN set -x \
         perl \
         python3
 COPY znc-build-modules.sh /
-
-# Revert the USER root line above
-USER znc
diff --git a/slim/Dockerfile b/slim/Dockerfile
index d3e785b..8bfe4e3 100644
--- a/slim/Dockerfile
+++ b/slim/Dockerfile
@@ -20,6 +20,7 @@ RUN set -x \
         cyrus-sasl \
         icu \
         openssl \
+        sudo \
         tini \
     && apk add --no-cache --virtual build-dependencies \
         build-base \
@@ -47,7 +48,6 @@ RUN set -x \
 
 COPY docker-entrypoint.sh /
 
-USER znc
 VOLUME /znc-data
 
 ENTRYPOINT ["/docker-entrypoint.sh"]
diff --git a/slim/docker-entrypoint.sh b/slim/docker-entrypoint.sh
index 5b06172..ce4d6dd 100755
--- a/slim/docker-entrypoint.sh
+++ b/slim/docker-entrypoint.sh
@@ -9,11 +9,6 @@ fi
 # Options.
 DATADIR="/znc-data"
 
-# Make sure $DATADIR is owned by znc user. This affects ownership of the
-# mounted directory on the host machine too.
-chown -R znc:znc "$DATADIR" || exit 1
-chmod 700 "$DATADIR" || exit 2
-
 # This file is added by znc:full image
 if [ -r /znc-build-modules.sh ]; then
     source /znc-build-modules.sh || exit 3
@@ -21,6 +16,12 @@ fi
 
 cd /
 
+# Make sure $DATADIR is owned by znc user. This affects ownership of the
+# mounted directory on the host machine too.
+chown -R znc:znc "$DATADIR" || exit 1
+chmod 700 "$DATADIR" || exit 2
+
 # ZNC itself responds to SIGTERM, and reaps its children, but whatever was
 # started via *shell module is not guaranteed to reap their children.
-exec /sbin/tini -- /opt/znc/bin/znc --foreground --datadir "$DATADIR" "$@"
+# That's why using tini.
+exec /sbin/tini -- sudo --user znc /opt/znc/bin/znc --foreground --datadir "$DATADIR" "$@"