diff --git a/script/update_libgit2 b/script/update_libgit2
index d84cb1de..58bf29f8 100755
--- a/script/update_libgit2
+++ b/script/update_libgit2
@@ -7,32 +7,161 @@ set -e
 # ~/.MacOSX/environment.plist
 PATH="/usr/local/bin:$PATH"
 
-if [ "External/libgit2.a" -nt "External/libgit2" ]
-then
-    echo "No update needed."
-    exit 0
-fi
+SCRIPT_DIR=$(dirname "$0")
+source "${SCRIPT_DIR}/xcode_functions.sh"
 
-cd "External/libgit2"
+function setup_build_environment ()
+{
+    # augment path to help it find cmake installed in /usr/local/bin,
+    # e.g. via brew. Xcode's Run Script phase doesn't seem to honor
+    # ~/.MacOSX/environment.plist
+    PATH="/usr/local/bin:$PATH"
 
-if [ -d "build" ]; then
+    pushd "$SCRIPT_DIR/.." > /dev/null
+    ROOT_PATH="$PWD"
+    popd > /dev/null
+
+    CLANG="/usr/bin/xcrun clang"
+    CC="${CLANG}"
+    CPP="${CLANG} -E"
+
+    # We need to clear this so that cmake doesn't have a conniption
+    MACOSX_DEPLOYMENT_TARGET=""
+
+    XCODE_MAJOR_VERSION=$(xcode_major_version)
+    XCODE_MINOR_VERSION=$(xcode_minor_version)
+
+    CAN_BUILD_ARM="0"
+
+    # Determine if we can be building for ARM Macs
+    if [ "${XCODE_MAJOR_VERSION}" -ge "12" ] && [ "${XCODE_MINOR_VERSION}" -ge "2" ]
+    then
+        CAN_BUILD_ARM="1"
+    fi
+
+    ARCHS="x86_64"
+    if [ "${CAN_BUILD_ARM}" -eq "1" ]
+    then
+        ARCHS="${ARCHS} arm64 arm64e"
+    fi
+}
+
+function build_all_archs ()
+{
+    setup_build_environment
+
+    local setup=$1
+    local build_arch=$2
+    local finish_build=$3
+
+    # run the prepare function
+    eval $setup
+
+    echo "Building for ${ARCHS}"
+
+    for ARCH in ${ARCHS}
+    do
+        PLATFORM="macos"
+        SDKVERSION=$(ios_sdk_version)
+
+        # if [ "${ARCH}" == "arm64" ]
+        # then
+        #     HOST="aarch64-apple-darwin"
+        # else
+        #     HOST="${ARCH}-apple-darwin"
+        # fi
+
+        SDKNAME="${PLATFORM}${SDKVERSION}"
+        SDKROOT="$(ios_sdk_path ${SDKNAME})"
+
+        echo "Building ${LIBRARY_NAME} for ${SDKNAME} ${ARCH}"
+        echo "Please stand by..."
+
+        # run the per arch build command
+        eval $build_arch
+    done
+
+    # finish the build (usually lipo)
+    eval $finish_build
+}
+
+function setup ()
+{
+    if [ "${ROOT_PATH}/External/libgit2-mac/libgit2-mac.a" -nt "${ROOT_PATH}/External/libgit2" ]
+    then
+        echo "No update needed."
+        exit 0
+    fi
+
+    LIBRARY_NAME="libgit2"
+    LIB_PATH="${ROOT_PATH}/External/libgit2-mac"
+    rm -rf "${LIB_PATH}"
+
+    pushd "${ROOT_PATH}/External/libgit2" > /dev/null
+}
+
+function build_libgit2 ()
+{
     rm -rf "build"
-fi
-
-mkdir build
-cd build
-
-cmake -DBUILD_SHARED_LIBS:BOOL=OFF \
-    -DLIBSSH2_INCLUDE_DIRS:PATH=/usr/local/include/ \
-    -DBUILD_CLAR:BOOL=OFF \
-    -DTHREADSAFE:BOOL=ON \
-    ..
-cmake --build .
-
-product="libgit2.a"
-install_path="../../${product}"
-if [ "${product}" -nt "${install_path}" ]; then
-    cp -v "${product}" "${install_path}"
-fi
+    mkdir "build"
+
+    pushd "build" > /dev/null
+
+    # LOL Cmake
+    #if [ "${ARCH}" != "i386" ] && [ "${ARCH}" != "x86_64" ]
+    #then
+        #SYS_ROOT="-DCMAKE_OSX_SYSROOT=${SDKROOT}"
+    #fi
+
+    # install the each built arch somewhere sane
+    INSTALL_PREFIX="${LIB_PATH}/${SDKNAME}-${ARCH}.sdk"
+
+    mkdir -p "${INSTALL_PREFIX}"
+
+    LOG="${INSTALL_PREFIX}/build-libgit2.log"
+    echo "$LOG"
+
+
+    # cmake -DBUILD_SHARED_LIBS:BOOL=OFF \
+    #     -DLIBSSH2_INCLUDE_DIRS:PATH=/usr/local/include/ \
+    #     -DBUILD_CLAR:BOOL=OFF \
+    #     -DTHREADSAFE:BOOL=ON \
+    #     ..
+    # cmake --build .
+
+    cmake \
+        -DCMAKE_C_COMPILER_WORKS:BOOL=ON \
+        -DBUILD_SHARED_LIBS:BOOL=OFF \
+        -DCMAKE_PREFIX_PATH:PATH="${ROOT_PATH}/External/libssh2-mac/bin/${SDKNAME}-${ARCH}.sdk" \
+        -DPKG_CONFIG_USE_CMAKE_PREFIX_PATH:BOOL=ON \
+        -DCMAKE_INSTALL_PREFIX:PATH="${INSTALL_PREFIX}/" \
+        -DBUILD_CLAR:BOOL=OFF \
+        -DTHREADSAFE:BOOL=ON \
+        -DCURL:BOOL=OFF \
+        -DCMAKE_C_FLAGS:STRING="-fembed-bitcode" \
+        "${SYS_ROOT}" \
+        -DCMAKE_OSX_ARCHITECTURES:STRING="${ARCH}" \
+        .. >> "${LOG}" 2>&1
+    cmake --build . --target install >> "${LOG}" 2>&1
+
+    # push the built library into the list
+    BUILT_LIB_PATHS+=("${INSTALL_PREFIX}/lib/libgit2.a")
+    popd > /dev/null
+}
+
+function fat_binary ()
+{
+    echo "Building fat binary..."
+
+    lipo -create "${BUILT_LIB_PATHS[@]}" -output "${ROOT_PATH}/External/libgit2-mac/libgit2-mac.a"
+
+    echo "Building done."
+
+    popd > /dev/null
+}
+
+
+build_all_archs setup build_libgit2 fat_binary
+
 
 echo "libgit2 has been updated."