diff --git a/.gitignore b/.gitignore
index 445cbf7..bed986d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -426,3 +426,8 @@ lib/cocos_old/
 lib/Dobby_old/
 sign.bat
 sign.sh
+jarsign.sh
+
+# Android NDK, build-tools
+/ndk/
+/abt/
diff --git a/build_release.sh b/build_release.sh
index c4df506..0ddef8e 100644
--- a/build_release.sh
+++ b/build_release.sh
@@ -8,8 +8,9 @@ NINJA="${MT_NINJA:-ninja}" # /usr/bin/ninja
 CURL="${MT_CURL:-curl}" # /usr/bin/curl
 JAVA="${MT_JAVA:-java}" # /usr/bin/java
 PYTHON="${MT_PYTHON:-python3}" # /usr/bin/python3.8
-JARSIGNER="${MT_JARSIGNER:-jarsigner}" # /usr/bin/jarsigner
-APKTOOL="${MT_APKTOOL:-apktool_2.5.0.jar}"
+APKTOOL="${MT_APKTOOL:-apktool_2.6.0.jar}"
+ZIPALIGN="${MT_ZIPALIGN:-zipalign}" # ~/android-sdk/build-tools/zipalign
+APKSIGNER="${MT_APKSIGNER:-apksigner}" # ~/android-sdk/build-tools/apksigner
 
 # arg-based
 SRCAPK="${1:-${BASEDIR}/apk/vanilla.apk}"
diff --git a/sign_example.sh b/sign_example.sh
index 5327013..9d464a3 100644
--- a/sign_example.sh
+++ b/sign_example.sh
@@ -2,21 +2,34 @@
 BASEDIR="$(realpath "$(dirname "${0}")")"
 
 # env-based
-JARSIGNER="${MT_JARSIGNER:-jarsigner}" # /usr/bin/jarsigner
+ZIPALIGN="${MT_ZIPALIGN:-zipalign}" # ~/android-sdk/build-tools/zipalign
+APKSIGNER="${MT_APKSIGNER:-apksigner}" # ~/android-sdk/build-tools/apksigner
+
+# hardcode-based
+#ZIPALIGN="${BASEDIR}/abt/zipalign"
+#APKSIGNER="${BASEDIR}/abt/apksigner"
 
 # arg-based
 APK="${1:-${BASEDIR}/build/io.kamihama.magiatranslate.v0.50.apk}"
 KEYSTORE="${2:-${BASEDIR}/changeme.keystore}"
 
-if [ ! -f "${APK}" ]
-then
-	echo "Missing apk to sign! Tried file: ${APK}"
-	exit 1
-fi
-if [ ! -f "${KEYSTORE}" ]
-then
-	echo "Missing keystore! Tried file: ${KEYSTORE}"
-	exit 2
-fi
+_errorexit() {
+	[ -z "${2}" ] || echo "${2}"
+	echo "Signing failed."
+	exit ${1}
+}
 
-${JARSIGNER} -sigalg SHA512withRSA -digestalg SHA-512 -keystore "${KEYSTORE}" "${APK}" -storepass changeme name
+[ -f "${APK}" ] || _errorexit 1 "Missing apk to sign! Tried file: ${APK}"
+[ -f "${KEYSTORE}" ] || _errorexit 2 "Missing keystore! Tried file: ${KEYSTORE}"
+
+echo "Doing zipalign..."
+"${ZIPALIGN}" -f -p 4 "${APK}" "${APK}.tmp"
+[ "$?" -ne "0" ] && _errorexit 3 "Failed to zipalign!"
+
+echo "Doing apksign..."
+"${APKSIGNER}" sign --ks "${KEYSTORE}" --ks-pass pass:changeme --ks-key-alias name "${APK}.tmp"
+[ "$?" -ne "0" ] && _errorexit 4 "Failed to apksign!"
+
+echo "Removing tmp file..."
+mv "${APK}.tmp" "${APK}"
+exit 0