diff --git a/.github/workflows/cross.yml b/.github/workflows/cross.yml
index bd799f9d136..cf8a9e5281c 100644
--- a/.github/workflows/cross.yml
+++ b/.github/workflows/cross.yml
@@ -140,7 +140,7 @@ jobs:
 
   aws-lc-rs-windows-gnu:
     if: github.repository_owner == 'aws'
-    name: ${{ matrix.target }} ${{ (matrix.ninja == '1' && 'w/ Ninja') || 'w/o Ninja'}}
+    name: ${{ matrix.target }}
     runs-on: windows-latest
     strategy:
       fail-fast: false
@@ -148,17 +148,11 @@ jobs:
         target:
           - 'x86_64-pc-windows-gnu'
           # TODO: 'i686-pc-windows-gnu'
-        ninja:
-          - '0'
-          - '1'
     steps:
       - uses: ilammy/setup-nasm@v1
       - uses: actions/checkout@v4
         with:
           submodules: 'recursive'
-      - name: Install ninja-build tool
-        if: ${{ matrix.ninja == '1' }}
-        uses: seanmiddleditch/gha-setup-ninja@v4
       - uses: dtolnay/rust-toolchain@master
         id: toolchain
         with:
@@ -171,7 +165,7 @@ jobs:
 
   aws-lc-rs-windows-msvc:
     if: ${{ github.repository_owner == 'aws' }}
-    name: ${{ matrix.target }} ${{ (matrix.ninja == '1' && 'w/ Ninja') || 'w/o Ninja'}} - ${{ (matrix.crt_static == '1' && '/WX and crt-static') || '/WX' }}
+    name: ${{ matrix.target }} - ${{ (matrix.crt_static == '1' && 'crt-static and /WX') || '/WX' }}
     runs-on: windows-latest
     strategy:
       fail-fast: false
@@ -180,9 +174,6 @@ jobs:
           - 'x86_64-pc-windows-msvc'
           - 'i686-pc-windows-msvc'
           - 'aarch64-pc-windows-msvc'
-        ninja:
-          - '0'
-          - '1'
         crt_static:
           - '0'
           - '1'
@@ -194,7 +185,7 @@ jobs:
         with:
           submodules: 'recursive'
       - name: Install ninja-build tool
-        if: ${{ matrix.ninja == '1' }}
+        if: ${{ matrix.target == 'aarch64-pc-windows-msvc' }}
         uses: seanmiddleditch/gha-setup-ninja@v4
       - uses: dtolnay/rust-toolchain@master
         id: toolchain
@@ -216,8 +207,6 @@ jobs:
             echo "RUSTFLAGS=-Clink-arg=/WX" | Out-File -FilePath $env:GITHUB_ENV -Append
           }
       - name: Debug build
-        if: ${{ matrix.target != 'aarch64-pc-windows-msvc' || matrix.ninja == '1' }}
         run: cargo ${{ env.ACTION_CARGO }} -p aws-lc-rs --all-targets --target ${{ matrix.target }} --features bindgen
       - name: Release Build for ${{ matrix.target }}
-        if: ${{ matrix.target != 'aarch64-pc-windows-msvc' || matrix.ninja == '1' }}
         run: cargo ${{ env.ACTION_CARGO }} --release -p aws-lc-rs --all-targets --target ${{ matrix.target }}
diff --git a/aws-lc-fips-sys/builder/main.rs b/aws-lc-fips-sys/builder/main.rs
index da6de18856a..ac5d5ed5c93 100644
--- a/aws-lc-fips-sys/builder/main.rs
+++ b/aws-lc-fips-sys/builder/main.rs
@@ -144,7 +144,7 @@ pub(crate) struct TestCommandResult {
     status: bool,
 }
 
-const MAX_CMD_OUTPUT_SIZE: usize = 1 << 14;
+const MAX_CMD_OUTPUT_SIZE: usize = 1 << 15;
 fn execute_command(executable: &OsStr, args: &[&OsStr]) -> TestCommandResult {
     if let Ok(mut result) = Command::new(executable).args(args).output() {
         result.stderr.truncate(MAX_CMD_OUTPUT_SIZE);
diff --git a/aws-lc-sys/builder/cmake_builder.rs b/aws-lc-sys/builder/cmake_builder.rs
index 894919139a2..5a8f541d3af 100644
--- a/aws-lc-sys/builder/cmake_builder.rs
+++ b/aws-lc-sys/builder/cmake_builder.rs
@@ -6,6 +6,7 @@ use crate::{
     cargo_env, emit_warning, execute_command, is_crt_static, is_no_asm, option_env, target,
     target_arch, target_env, target_os, target_underscored, target_vendor, OutputLibType,
 };
+use std::collections::HashMap;
 use std::env;
 use std::ffi::OsStr;
 use std::path::PathBuf;
@@ -168,23 +169,26 @@ impl CmakeBuilder {
         }
 
         if target_underscored() == "aarch64_pc_windows_msvc" {
-            //cmake_cfg.generator("Ninja");
-            cmake_cfg.define("CMAKE_C_COMPILER", "clang-cl");
-            cmake_cfg.define("CMAKE_CXX_COMPILER", "clang-cl");
-            cmake_cfg.define("CMAKE_ASM_COMPILER", "clang-cl");
-            // If the build host is not aarch64
-            #[cfg(not(target_arch = "aarch64"))]
-            {
-                // Only needed when cross-compiling
-                cmake_cfg.define("CMAKE_SYSTEM_PROCESSOR", "ARM64");
-                cmake_cfg.define("CMAKE_C_FLAGS_INIT", "--target=arm64-pc-windows-msvc");
-                cmake_cfg.define("CMAKE_CXX_FLAGS_INIT", "--target=arm64-pc-windows-msvc");
-                cmake_cfg.define("CMAKE_ASM_FLAGS_INIT", "--target=arm64-pc-windows-msvc");
-
-                cmake_cfg.define("CMAKE_FIND_ROOT_PATH_MODE_PROGRAM", "NEVER");
-                cmake_cfg.define("CMAKE_FIND_ROOT_PATH_MODE_LIBRARY", "ONLY");
-                cmake_cfg.define("CMAKE_FIND_ROOT_PATH_MODE_INCLUDE", "ONLY");
-                cmake_cfg.define("CMAKE_FIND_ROOT_PATH_MODE_INCLUDE", "ONLY");
+            cmake_cfg.generator("Ninja");
+            cmake_cfg.define("CMAKE_ASM_COMPILER_TARGET", "arm64-pc-windows-msvc");
+            // Only needed when cross-compiling
+            let env_map = self
+                .collect_vcvarsall_bat()
+                .map_err(|x| panic!("{}", x))
+                .unwrap();
+            let mut assembler_set = false;
+            for (key, value) in env_map {
+                if key == "VCINSTALLDIR" {
+                    cmake_cfg.define(
+                        "CMAKE_ASM_COMPILER",
+                        format!("{}Tools\\Llvm\\bin\\clang-cl.exe", value),
+                    );
+                    assembler_set = true;
+                }
+                cmake_cfg.env(key, value);
+            }
+            if !assembler_set {
+                panic!("No assmebler set");
             }
         }
 
@@ -210,6 +214,24 @@ impl CmakeBuilder {
             .configure_arg("--no-warn-unused-cli")
             .build()
     }
+
+    fn collect_vcvarsall_bat(&self) -> Result<HashMap<String, String>, String> {
+        let mut map: HashMap<String, String> = HashMap::new();
+        let script_path = self.manifest_dir.join("builder").join("printenv.bat");
+        let result = execute_command(script_path.as_os_str(), &[]);
+        if !result.status {
+            eprintln!("{}", result.stdout);
+            return Err("Failed to run vcvarsall.bat.".to_owned());
+        }
+        eprintln!("{}", result.stdout);
+        let lines = result.stdout.lines();
+        for line in lines {
+            if let Some((var, val)) = line.split_once('=') {
+                map.insert(var.to_string(), val.to_string());
+            }
+        }
+        Ok(map)
+    }
 }
 
 impl crate::Builder for CmakeBuilder {
diff --git a/aws-lc-sys/builder/main.rs b/aws-lc-sys/builder/main.rs
index bf3e9fffee0..7207df794a2 100644
--- a/aws-lc-sys/builder/main.rs
+++ b/aws-lc-sys/builder/main.rs
@@ -142,7 +142,7 @@ pub(crate) struct TestCommandResult {
     status: bool,
 }
 
-const MAX_CMD_OUTPUT_SIZE: usize = 1 << 12;
+const MAX_CMD_OUTPUT_SIZE: usize = 1 << 15;
 fn execute_command(executable: &OsStr, args: &[&OsStr]) -> TestCommandResult {
     if let Ok(mut result) = Command::new(executable).args(args).output() {
         result.stderr.truncate(MAX_CMD_OUTPUT_SIZE);
diff --git a/aws-lc-sys/builder/printenv.bat b/aws-lc-sys/builder/printenv.bat
new file mode 100644
index 00000000000..b39f13e929c
--- /dev/null
+++ b/aws-lc-sys/builder/printenv.bat
@@ -0,0 +1,44 @@
+@echo off
+setlocal EnableDelayedExpansion
+
+set "TOP_DIR=%ProgramFiles(x86)%\Microsoft Visual Studio"
+for /f "usebackq tokens=* delims=" %%i in (`"%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\vswhere.exe" -latest -property installationPath`) do (
+    set "TOP_DIR=%%i"
+    echo VS Installation: "!TOP_DIR!"
+    if exist "!TOP_DIR!\VC\Auxiliary\Build\vcvarsall.bat" (
+        set "VS_PATH=!TOP_DIR!\VC\Auxiliary\Build\"
+        echo FOUND in Installation: "!VS_PATH!"
+        goto FoundVS
+    )
+    goto SearchVS
+)
+
+echo Visual Studio installation not found using vswhere. Searching in default directories...
+
+:SearchVS
+for /R "%TOP_DIR%" %%a in (vcvarsall.bat) do (
+    if exist "%%~fa" (
+        set "VS_PATH=%%~dpa"
+        echo FOUND: "!VS_PATH!"
+        goto FoundVS
+    )
+)
+echo vcvarsall.bat not found.
+goto End
+
+:FoundVS
+call "!VS_PATH!vcvarsall.bat" x86_arm64
+if !ERRORLEVEL! neq 0 (
+    echo Failed to set Visual Studio environment variables.
+    echo PATH: "!VS_PATH!vcvarsall.bat"
+    goto End
+)
+echo Visual Studio environment variables set for x64.
+
+set
+endlocal
+exit /b 0
+
+:End
+endlocal
+exit /b 1