diff --git a/linux/build_release.sh b/linux/build_release.sh
index bf9437c..42a66bb 100755
--- a/linux/build_release.sh
+++ b/linux/build_release.sh
@@ -12,8 +12,8 @@ set -euo pipefail
 
 platform="${1:-x86_64}"
 case "${platform}" in
-  x86_64) arch="x86_64-unknown-linux-gnu" ;;
-  arm)    arch="aarch64-unknown-linux-gnu" ;;
+  x86_64) arch="x86_64-unknown-linux-gnu"; appimage_arch="x86_64" ;;
+  arm)    arch="aarch64-unknown-linux-gnu"; appimage_arch="aarch64" ;;
   *) echo "Usage: build_release.sh [platform]  (platform: 'x86_64' | 'arm')" >&2; exit 1 ;;
 esac
 
@@ -51,7 +51,13 @@ out="target/${arch}/release/Goblin-${platform}.AppImage"
 rm -f "target/${arch}/release/"*.AppImage
 # Use the DEV appimagetool + type2 runtime when fetched, else the system tool.
 appimagetool_bin="${GOBLIN_APPIMAGETOOL:-appimagetool}"
+# The type2 runtime must match the target arch. env.sh sets GOBLIN_APPIMAGE_RUNTIME
+# to the x86_64 runtime; for a non-x86_64 target use the sibling runtime-<arch>.
+runtime_file="${GOBLIN_APPIMAGE_RUNTIME:-}"
+if [ "${appimage_arch}" != "x86_64" ] && [ -n "${runtime_file}" ]; then
+  runtime_file="$(dirname "${runtime_file}")/runtime-${appimage_arch}"
+fi
 runtime_arg=()
-[ -n "${GOBLIN_APPIMAGE_RUNTIME:-}" ] && runtime_arg=(--runtime-file "${GOBLIN_APPIMAGE_RUNTIME}")
-ARCH=x86_64 "${appimagetool_bin}" "${runtime_arg[@]}" "${appdir}" "${out}"
+[ -n "${runtime_file}" ] && [ -e "${runtime_file}" ] && runtime_arg=(--runtime-file "${runtime_file}")
+ARCH="${appimage_arch}" "${appimagetool_bin}" "${runtime_arg[@]}" "${appdir}" "${out}"
 echo "built: ${out}"
diff --git a/scripts/toolchain.sh b/scripts/toolchain.sh
index d3fe640..2a95e29 100755
--- a/scripts/toolchain.sh
+++ b/scripts/toolchain.sh
@@ -49,11 +49,12 @@ fetch_zig() {
 }
 
 fetch_appimage() {
-	[ -x "${TC}/appimagetool" ] && [ -e "${TC}/runtime-x86_64" ] && { echo "appimagetool ${AT_VER}: present"; return; }
-	echo "appimage: fetching appimagetool ${AT_VER} + type2 runtime…"
+	[ -x "${TC}/appimagetool" ] && [ -e "${TC}/runtime-x86_64" ] && [ -e "${TC}/runtime-aarch64" ] && { echo "appimagetool ${AT_VER}: present"; return; }
+	echo "appimage: fetching appimagetool ${AT_VER} + type2 runtimes (x86_64 + aarch64)…"
 	dl "${DEV}/appimagetool/releases/download/${AT_VER}/appimagetool-x86_64.AppImage" "${TC}/appimagetool"
 	dl "${DEV}/appimage-type2-runtime/releases/download/${RT_TAG}/runtime-x86_64" "${TC}/runtime-x86_64"
-	chmod +x "${TC}/appimagetool" "${TC}/runtime-x86_64"
+	dl "${DEV}/appimage-type2-runtime/releases/download/${RT_TAG}/runtime-aarch64" "${TC}/runtime-aarch64"
+	chmod +x "${TC}/appimagetool" "${TC}/runtime-x86_64" "${TC}/runtime-aarch64"
 }
 
 # Assemble a minimal Android SDK (build-tools + platform + platform-tools) from