Add rtl_tcp_andro as submodule for SDR driver app

RTL-SDR + HackRF native Android driver (iqsrc:// protocol).
Auto-installs APK during module flash if built. Build docs
updated with instructions.

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "tools/rtl_tcp_andro"]
+	path = tools/rtl_tcp_andro
+	url = https://github.com/signalwareltd/rtl_tcp_andro-.git

BUILDING_MODULES.md

@@ -32,6 +32,33 @@ Some features need extra firmware or kernel modules you build yourself.
 **No kernel modules needed.** All SDR devices on Android use userspace USB libraries.
 The module handles USB permissions automatically.
 
+**RTL-SDR + HackRF Driver App (rtl_tcp_andro):**
+
+This module includes the source for the Android RTL-SDR/HackRF driver app
+([rtl_tcp_andro](https://github.com/signalwareltd/rtl_tcp_andro-.git)) as a
+submodule in `tools/rtl_tcp_andro/`. It implements the rtl_tcp protocol natively
+on Android via USB OTG — no root needed for the app itself.
+
+To build the APK:
+```bash
+cd tools/rtl_tcp_andro
+./gradlew assembleRelease
+```
+
+The APK will be at `app/build/outputs/apk/release/app-release-unsigned.apk`.
+Copy it to `apk/rtl_tcp_andro.apk` and rebuild the module zip — the installer
+will auto-install it on the device.
+
+Or install directly:
+```bash
+adb install app/build/outputs/apk/release/app-release-unsigned.apk
+```
+
+The app provides an `iqsrc://` intent that any SDR client app can use to
+receive I/Q samples from RTL-SDR, HackRF, or SDRplay hardware.
+
+Supported hardware: RTL-SDR (all versions), HackRF One, SDRplay RSP
+
 **Setup in Termux:**
 
 ```bash

build.sh

@@ -5,14 +5,31 @@ cd "$(dirname "$0")"
 ZIP="driver-manager-v1.0.0.zip"
 rm -f "$ZIP"
 
-zip -r9 "$ZIP" \
-    module.prop \
-    customize.sh \
-    post-fs-data.sh \
-    service.sh \
-    system.prop \
-    system/ \
-    webroot/ \
+# Include built APK if available
+mkdir -p apk
+RTL_APK="tools/rtl_tcp_andro/app/build/outputs/apk/release/app-release-unsigned.apk"
+if [ -f "$RTL_APK" ]; then
+    cp "$RTL_APK" apk/rtl_tcp_andro.apk
+    echo "Including rtl_tcp_andro APK"
+fi
+
+FILES=(
+    module.prop
+    customize.sh
+    post-fs-data.sh
+    service.sh
+    system.prop
+    system/
+    webroot/
+    BUILDING_MODULES.md
+)
+
+# Include APK dir if it has files
+if [ -f "apk/rtl_tcp_andro.apk" ]; then
+    FILES+=(apk/)
+fi
+
+zip -r9 "$ZIP" "${FILES[@]}" \
     -x "*.git*" "build.sh" "tools/*" "README*"
 
 echo "Built: $ZIP ($(du -h "$ZIP" | cut -f1))"

customize.sh

@@ -46,6 +46,21 @@ echo "24M:1800M" > "$MODPATH/config/spectrum_range"
 mkdir -p "$MODPATH/modules"
 mkdir -p "$MODPATH/firmware"
 
+# Install rtl_tcp_andro APK if built
+RTL_APK="$MODPATH/apk/rtl_tcp_andro.apk"
+if [ -f "$RTL_APK" ]; then
+    pm install -r "$RTL_APK" 2>/dev/null
+    if [ $? -eq 0 ]; then
+        ui_print "- RTL-SDR + HackRF driver app installed"
+    else
+        ui_print "! Failed to install RTL-SDR driver app"
+        ui_print "! Install manually from apk/ directory"
+    fi
+else
+    ui_print "- RTL-SDR driver app not built yet"
+    ui_print "  Build with: cd tools/rtl_tcp_andro && ./gradlew assembleRelease"
+fi
+
 ui_print "- Default config written"
 ui_print "- Kernel module dir: modules/"
 ui_print "- Firmware dir: firmware/"