diff --git a/Dockerfile b/Dockerfile
index d1ac931..9686b0d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,38 +2,35 @@
 
 FROM alpine:3.23 AS rootfs-stage
 
+ARG TARGETARCH
 ARG S6_OVERLAY_VERSION="3.2.2.0"
 ARG ROOTFS=/root-out
 ARG REL=v3.23
-ARG ARCH=x86_64
 ARG MIRROR=http://dl-cdn.alpinelinux.org/alpine
-ARG PACKAGES=alpine-baselayout,\
-alpine-keys,\
-apk-tools,\
-busybox,\
-libc-utils
+ARG PACKAGES=alpine-baselayout,alpine-keys,apk-tools,busybox,libc-utils
 
-# install packages
-RUN \
-  apk add --no-cache \
-    bash \
-    xz
+RUN apk add --no-cache bash xz curl ca-certificates
+
+# map arch
+RUN case "${TARGETARCH}" in \
+      amd64)  echo "x86_64"  > /arch ;; \
+      arm64)  echo "aarch64" > /arch ;; \
+      *) echo "unsupported arch" && exit 1 ;; \
+    esac
 
 # build rootfs
-RUN \
-  mkdir -p "${ROOTFS}/etc/apk" && \
-  { \
-    echo "${MIRROR}/${REL}/main"; \
-    echo "${MIRROR}/${REL}/community"; \
-  } > "${ROOTFS}/etc/apk/repositories" && \
-  apk --root "${ROOTFS}" --no-cache --keys-dir /etc/apk/keys add --arch ${ARCH} --initdb ${PACKAGES//,/ } && \
-  sed -i -e 's/^root::/root:!:/' /root-out/etc/shadow
+RUN mkdir -p "${ROOTFS}/etc/apk" && \
+    echo "${MIRROR}/${REL}/main" > "${ROOTFS}/etc/apk/repositories" && \
+    echo "${MIRROR}/${REL}/community" >> "${ROOTFS}/etc/apk/repositories" && \
+    apk --root "${ROOTFS}" --no-cache --initdb ${PACKAGES//,/ } && \
+    sed -i 's/^root::/root:!:/' "${ROOTFS}/etc/shadow"
 
-# add s6 overlay
-ADD https://github.com/just-containers/s6-overlay/releases/download/v${S6_OVERLAY_VERSION}/s6-overlay-noarch.tar.xz /tmp
-RUN tar -C /root-out -Jxpf /tmp/s6-overlay-noarch.tar.xz
-ADD https://github.com/just-containers/s6-overlay/releases/download/v${S6_OVERLAY_VERSION}/s6-overlay-${ARCH}.tar.xz /tmp
-RUN tar -C /root-out -Jxpf /tmp/s6-overlay-${ARCH}.tar.xz
+# s6 overlay
+RUN ARCH="$(cat /arch)" && \
+    curl -fsSL https://github.com/just-containers/s6-overlay/releases/download/v${S6_OVERLAY_VERSION}/s6-overlay-noarch.tar.xz \
+      | tar -C "${ROOTFS}" -Jxpf - && \
+    curl -fsSL https://github.com/just-containers/s6-overlay/releases/download/v${S6_OVERLAY_VERSION}/s6-overlay-${ARCH}.tar.xz \
+      | tar -C "${ROOTFS}" -Jxpf -
 
 # add s6 optional symlinks
 ADD https://github.com/just-containers/s6-overlay/releases/download/v${S6_OVERLAY_VERSION}/s6-overlay-symlinks-noarch.tar.xz /tmp