diff --git a/.ci/package-mac.sh b/.ci/package-mac.sh
index 48263d0..59ade2e 100644
--- a/.ci/package-mac.sh
+++ b/.ci/package-mac.sh
@@ -16,11 +16,11 @@ set -e
 # Modify the package with the solution from https://stackoverflow.com/a/11299907
 # First, download the package and extract it
 wget https://github.com/rime/squirrel/releases/download/${SQUIRREL_VERSION}/Squirrel-${SQUIRREL_VERSION}.pkg
-pkgutil --expand Squirrel-${SQUIRREL_VERSION}.pkg package
 pushd package
+xar -xf ../Squirrel-${SQUIRREL_VERSION}.pkg
 
 # Extract the application
-tar -xzf Payload
+cat Payload | gunzip -dc | cpio -i
 pushd Squirrel.app/Contents
 
 # Remove all default rime schemas but keep opencc data and app config
@@ -31,33 +31,19 @@ cp -rf "$SCHEMA_DIR/"* SharedSupport
 popd
 
 # Resign the application
-for binary in $(codesign -v -vv --deep --strict Squirrel.app 2>&1 | sed -n 's/^--validated://p') Squirrel.app; do
-  echo "----------"
-  echo "Signing $binary"
-  codesign --sign "Developer ID Application: $APPLE_DEVELOPER_NAME ($APPLE_DEVELOPER_TEAM_ID)" -vvvvvv --timestamp --force --options runtime --preserve-metadata=identifier,entitlements "$binary"
-
-  echo
-  codesign -v -vv --deep --strict "$binary"
-done
+codesign --sign "Developer ID Application: $APPLE_DEVELOPER_NAME ($APPLE_DEVELOPER_TEAM_ID)" --timestamp --deep --force --options runtime --preserve-metadata=identifier,entitlements Squirrel.app
 
 # Compress back the application
 find Squirrel.app | cpio -o | gzip -c > Payload
 mkbom Squirrel.app Bom
 rm -rf Squirrel.app
-popd
 
 # Finally, compress back the package
-mkdir output
-pkgutil --flatten package output/Squirrel.pkg
-cd output
+mkdir ../output
+xar -cf ../output/Squirrel.pkg *
+popd
 
 # Resign the package
+cd output
 pkg_path=Squirrel-${SQUIRREL_VERSION}-rime-cantonese.pkg
 productsign --sign "Developer ID Installer: $APPLE_DEVELOPER_NAME ($APPLE_DEVELOPER_TEAM_ID)" Squirrel.pkg "$pkg_path"
-
-# Verify
-pkgutil --expand "$pkg_path" package
-cd package
-
-tar -xzf Payload
-codesign -v -vv --deep --strict "Squirrel.app"