diff --git a/scripts/install-node18-runtime.sh b/scripts/install-node18-runtime.sh
new file mode 100755
index 0000000..23e5757
--- /dev/null
+++ b/scripts/install-node18-runtime.sh
@@ -0,0 +1,115 @@
+#!/usr/bin/env bash
+# Batch 6 — swap the embedded runtime to Node 18.20.4.
+#
+# The published nodejs-mobile-cordova (0.4.3) and its community fork's `unstable`
+# branch both still ship Node 12.19.0 for Android. Node 18 for Android exists only
+# in the nodejs-mobile CORE release (github.com/nodejs-mobile/nodejs-mobile). This
+# script stages that core runtime into the installed plugin so the existing native
+# glue (native-lib.cpp calls node::Start, cordova-bridge is N-API) rebuilds against
+# Node 18 — verified: node::Start, AddLinkedBinding, and the N-API surface are all
+# present in the v18 libnode, and the SONAME is unchanged (libnode.so).
+#
+# node_modules/ is regenerated by `npm install`, so RE-RUN this after any install
+# (same pattern as fix-better-sqlite3-android.sh). Run from the mobile project root.
+#
+# Node 18 core ships arm64-v8a / armeabi-v7a / x86_64 only — there is no 32-bit x86
+# build, so the plugin's stale v12 x86 libnode is left untouched (x86 should be
+# dropped from abiFilters + prepare-android-assets.js in Batch 7).
+
+set -euo pipefail
+
+NODE_MOBILE_VERSION="18.20.4"
+ZIP_NAME="nodejs-mobile-v${NODE_MOBILE_VERSION}-android.zip"
+ZIP_URL="https://github.com/nodejs-mobile/nodejs-mobile/releases/download/v${NODE_MOBILE_VERSION}/${ZIP_NAME}"
+ABIS=(arm64-v8a armeabi-v7a x86_64)
+
+MOBILE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+PLUGIN_LIBNODE="$MOBILE_DIR/node_modules/nodejs-mobile-cordova/libs/android/libnode"
+CACHE_DIR="$MOBILE_DIR/build-output/nodejs-mobile-runtime"   # gitignored
+EXTRACT_DIR="$CACHE_DIR/nm18-android"
+
+if [[ ! -d "$PLUGIN_LIBNODE" ]]; then
+  echo "Error: nodejs-mobile-cordova not installed at $PLUGIN_LIBNODE" >&2
+  echo "Run 'npm install' first." >&2
+  exit 1
+fi
+
+mkdir -p "$CACHE_DIR"
+
+# 1. Fetch the core Android runtime (cached).
+if [[ ! -f "$CACHE_DIR/$ZIP_NAME" ]]; then
+  echo "Downloading $ZIP_NAME (~57 MB)…"
+  curl -fL --retry 3 -o "$CACHE_DIR/$ZIP_NAME" "$ZIP_URL"
+fi
+
+rm -rf "$EXTRACT_DIR"
+mkdir -p "$EXTRACT_DIR"
+unzip -q -o "$CACHE_DIR/$ZIP_NAME" -d "$EXTRACT_DIR"
+
+# 2. Swap libnode.so per ABI (plugin ships them gzipped; hook gunzips at build time).
+for abi in "${ABIS[@]}"; do
+  src="$EXTRACT_DIR/bin/$abi/libnode.so"
+  destdir="$PLUGIN_LIBNODE/bin/$abi"
+  if [[ ! -f "$src" ]]; then
+    echo "Error: missing $src in the core archive" >&2
+    exit 1
+  fi
+  mkdir -p "$destdir"
+  gzip -c "$src" > "$destdir/libnode.so.gz"
+  echo "  staged libnode.so.gz -> bin/$abi ($(du -h "$destdir/libnode.so.gz" | cut -f1))"
+done
+
+# 3. Swap headers (used to compile native-lib.cpp and native modules, e.g.
+#    better-sqlite3 in Batch 8).
+rm -rf "$PLUGIN_LIBNODE/include/node"
+mkdir -p "$PLUGIN_LIBNODE/include"
+cp -R "$EXTRACT_DIR/include/node" "$PLUGIN_LIBNODE/include/node"
+
+# 3.5 Patch the cordova-bridge linked-binding registration for Node 18.
+#
+# Node 18's NAPI_MODULE_X macro drops its priv/flags args and expands to the
+# symbol-based NAPI_MODULE registration, which Node only consumes when it
+# dlopen()s a .node file. cordova-bridge is compiled INTO the app's native lib,
+# so it was never registered and process._linkedBinding('cordova_bridge') failed
+# with "No such binding was linked". Register the linked binding explicitly via
+# the still-supported napi_module_register path (routes NM_F_LINKED modules into
+# the global modlist_linked at static-init, before node::Start). Idempotent.
+BRIDGE_CPP="$MOBILE_DIR/node_modules/nodejs-mobile-cordova/src/common/cordova-bridge/cordova-bridge.cpp"
+if [[ -f "$BRIDGE_CPP" ]]; then
+  python3 - "$BRIDGE_CPP" <<'PY'
+import sys
+p = sys.argv[1]
+src = open(p).read()
+old = "NAPI_MODULE_X(cordova_bridge, Init, NULL, NM_F_LINKED)"
+new = """static napi_module _cordova_bridge_module = {
+  NAPI_MODULE_VERSION,
+  NM_F_LINKED,
+  __FILE__,
+  Init,
+  "cordova_bridge",
+  NULL,
+  {0, 0, 0, 0},
+};
+__attribute__((constructor)) static void _register_cordova_bridge(void) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  napi_module_register(&_cordova_bridge_module);
+#pragma GCC diagnostic pop
+}"""
+if "_register_cordova_bridge" in src:
+    print("  cordova-bridge.cpp already patched for Node 18 linked binding")
+elif old in src:
+    open(p, "w").write(src.replace(old, new))
+    print("  patched cordova-bridge.cpp linked-binding registration for Node 18")
+else:
+    sys.exit("  ERROR: cordova-bridge.cpp registration line not found — plugin changed?")
+PY
+fi
+
+# 4. Confirm.
+ver_h="$PLUGIN_LIBNODE/include/node/node_version.h"
+maj=$(grep -E 'define NODE_MAJOR_VERSION' "$ver_h" | awk '{print $3}')
+min=$(grep -E 'define NODE_MINOR_VERSION' "$ver_h" | awk '{print $3}')
+pat=$(grep -E 'define NODE_PATCH_VERSION' "$ver_h" | awk '{print $3}')
+echo "Done. Plugin libnode headers now report Node ${maj}.${min}.${pat}."
+echo "Next: rebuild the app (npx cap sync android + gradle) and boot main.js to confirm process.version."