diff --git a/.github/workflows/bun-release-test.yml b/.github/workflows/bun-release-test.yml
new file mode 100644
index 0000000000..c331c47e93
--- /dev/null
+++ b/.github/workflows/bun-release-test.yml
@@ -0,0 +1,44 @@
+# This workflow tests bun-release's code and the packages to ensure that npm,
+# yarn, and pnpm can install bun on all platforms. This does not test that bun
+# itself works as it hardcodes 1.1.0 as the version to package.
+name: bun-release-test
+concurrency: release-test
+
+on:
+  pull_request:
+    paths:
+      - "packages/bun-release/**"
+      - ".github/workflows/bun-release-test.yml"
+
+jobs:
+  test-release-script:
+    name: Test Release Script
+    strategy:
+      matrix:
+        machine: [namespace-profile-bun-linux-x64, linux-arm64, macos-arm64, macos-12-large, windows-latest]
+      fail-fast: false
+    runs-on: ${{ matrix.machine }}
+    permissions:
+      contents: read
+    defaults:
+      run:
+        working-directory: packages/bun-release
+    timeout-minutes: 5
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v1
+        with:
+          bun-version: "1.1.0"
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+      - name: Install Dependencies
+        run: bun install && npm i -g pnpm yarn npm
+
+      - name: Release
+        run: bun upload-npm -- 1.1.0 test
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.gitignore b/.gitignore
index 32c68dc08c..3d3c40b760 100644
--- a/.gitignore
+++ b/.gitignore
@@ -140,4 +140,4 @@ txt.js
 x64
 yarn.lock
 zig-cache
-zig-out
+zig-out
\ No newline at end of file
diff --git a/packages/bun-release/.gitignore b/packages/bun-release/.gitignore
index 4c021cb09b..81f3bc7fe7 100644
--- a/packages/bun-release/.gitignore
+++ b/packages/bun-release/.gitignore
@@ -1,6 +1,8 @@
-.DS_Store
-.env
-node_modules
-/npm/**/bin
-/npm/**/*.js
-/npm/**/.npmrc
+.DS_Store
+.env
+node_modules
+/npm/**/bin
+/npm/**/*.js
+/npm/**/package.json
+/npm/**/.npmrc
+*.tgz
diff --git a/packages/bun-release/bun.lockb b/packages/bun-release/bun.lockb
index ab68b3a5de..5a23cb2ffb 100755
Binary files a/packages/bun-release/bun.lockb and b/packages/bun-release/bun.lockb differ
diff --git a/packages/bun-release/npm/@oven/bun-darwin-aarch64/package.json b/packages/bun-release/npm/@oven/bun-darwin-aarch64/package.json
deleted file mode 100644
index 701f4c92b8..0000000000
--- a/packages/bun-release/npm/@oven/bun-darwin-aarch64/package.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "name": "@oven/bun-darwin-aarch64",
-  "version": "0.5.3",
-  "description": "This is the macOS arm64 binary for Bun, a fast all-in-one JavaScript runtime.",
-  "homepage": "https://bun.sh",
-  "bugs": "https://github.com/oven-sh/issues",
-  "license": "MIT",
-  "repository": "https://github.com/oven-sh/bun",
-  "preferUnplugged": true,
-  "os": [
-    "darwin"
-  ],
-  "cpu": [
-    "arm64"
-  ]
-}
diff --git a/packages/bun-release/npm/@oven/bun-darwin-x64-baseline/package.json b/packages/bun-release/npm/@oven/bun-darwin-x64-baseline/package.json
deleted file mode 100644
index b14492c1c7..0000000000
--- a/packages/bun-release/npm/@oven/bun-darwin-x64-baseline/package.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "name": "@oven/bun-darwin-x64-baseline",
-  "version": "0.5.3",
-  "description": "This is the macOS x64 binary for Bun, a fast all-in-one JavaScript runtime.",
-  "homepage": "https://bun.sh",
-  "bugs": "https://github.com/oven-sh/issues",
-  "license": "MIT",
-  "repository": "https://github.com/oven-sh/bun",
-  "preferUnplugged": true,
-  "os": [
-    "darwin"
-  ],
-  "cpu": [
-    "x64"
-  ]
-}
diff --git a/packages/bun-release/npm/@oven/bun-darwin-x64/package.json b/packages/bun-release/npm/@oven/bun-darwin-x64/package.json
deleted file mode 100644
index 82934da0aa..0000000000
--- a/packages/bun-release/npm/@oven/bun-darwin-x64/package.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "name": "@oven/bun-darwin-x64",
-  "version": "0.5.3",
-  "description": "This is the macOS x64 binary for Bun, a fast all-in-one JavaScript runtime.",
-  "homepage": "https://bun.sh",
-  "bugs": "https://github.com/oven-sh/issues",
-  "license": "MIT",
-  "repository": "https://github.com/oven-sh/bun",
-  "preferUnplugged": true,
-  "os": [
-    "darwin"
-  ],
-  "cpu": [
-    "x64"
-  ]
-}
diff --git a/packages/bun-release/npm/@oven/bun-linux-aarch64/package.json b/packages/bun-release/npm/@oven/bun-linux-aarch64/package.json
deleted file mode 100644
index 4f68fec41b..0000000000
--- a/packages/bun-release/npm/@oven/bun-linux-aarch64/package.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "name": "@oven/bun-linux-aarch64",
-  "version": "0.5.3",
-  "description": "This is the Linux arm64 binary for Bun, a fast all-in-one JavaScript runtime.",
-  "homepage": "https://bun.sh",
-  "bugs": "https://github.com/oven-sh/issues",
-  "license": "MIT",
-  "repository": "https://github.com/oven-sh/bun",
-  "preferUnplugged": true,
-  "os": [
-    "linux"
-  ],
-  "cpu": [
-    "arm64"
-  ]
-}
diff --git a/packages/bun-release/npm/@oven/bun-linux-x64-baseline/package.json b/packages/bun-release/npm/@oven/bun-linux-x64-baseline/package.json
deleted file mode 100644
index 1767be0dc5..0000000000
--- a/packages/bun-release/npm/@oven/bun-linux-x64-baseline/package.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "name": "@oven/bun-linux-x64-baseline",
-  "version": "0.5.3",
-  "description": "This is the Linux x64 binary for Bun, a fast all-in-one JavaScript runtime.",
-  "homepage": "https://bun.sh",
-  "bugs": "https://github.com/oven-sh/issues",
-  "license": "MIT",
-  "repository": "https://github.com/oven-sh/bun",
-  "preferUnplugged": true,
-  "os": [
-    "linux"
-  ],
-  "cpu": [
-    "x64"
-  ]
-}
diff --git a/packages/bun-release/npm/@oven/bun-linux-x64/package.json b/packages/bun-release/npm/@oven/bun-linux-x64/package.json
deleted file mode 100644
index 16f9309f5d..0000000000
--- a/packages/bun-release/npm/@oven/bun-linux-x64/package.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "name": "@oven/bun-linux-x64",
-  "version": "0.5.3",
-  "description": "This is the Linux x64 binary for Bun, a fast all-in-one JavaScript runtime.",
-  "homepage": "https://bun.sh",
-  "bugs": "https://github.com/oven-sh/issues",
-  "license": "MIT",
-  "repository": "https://github.com/oven-sh/bun",
-  "preferUnplugged": true,
-  "os": [
-    "linux"
-  ],
-  "cpu": [
-    "x64"
-  ]
-}
diff --git a/packages/bun-release/npm/@oven/bun-windows-x64-baseline/README.md b/packages/bun-release/npm/@oven/bun-windows-x64-baseline/README.md
new file mode 100644
index 0000000000..0e383e2d8d
--- /dev/null
+++ b/packages/bun-release/npm/@oven/bun-windows-x64-baseline/README.md
@@ -0,0 +1,5 @@
+# Bun
+
+This is the Windows x64 binary for Bun, a fast all-in-one JavaScript runtime. https://bun.sh
+
+_Note: "Baseline" builds are for machines that do not support [AVX2](https://en.wikipedia.org/wiki/Advanced_Vector_Extensions) instructions._
diff --git a/packages/bun-release/npm/@oven/bun-windows-x64/README.md b/packages/bun-release/npm/@oven/bun-windows-x64/README.md
new file mode 100644
index 0000000000..1fa7a287ba
--- /dev/null
+++ b/packages/bun-release/npm/@oven/bun-windows-x64/README.md
@@ -0,0 +1,3 @@
+# Bun
+
+This is the Windows x64 binary for Bun, a fast all-in-one JavaScript runtime. https://bun.sh
diff --git a/packages/bun-release/npm/bun/package.json b/packages/bun-release/npm/bun/package.json
deleted file mode 100644
index 374518b855..0000000000
--- a/packages/bun-release/npm/bun/package.json
+++ /dev/null
@@ -1,42 +0,0 @@
-{
-  "name": "bun",
-  "version": "0.5.3",
-  "description": "Bun is a fast all-in-one JavaScript runtime.",
-  "keywords": [
-    "bun",
-    "bun.js",
-    "node",
-    "node.js",
-    "runtime",
-    "bundler",
-    "transpiler",
-    "typescript"
-  ],
-  "homepage": "https://bun.sh",
-  "bugs": "https://github.com/oven-sh/issues",
-  "license": "MIT",
-  "bin": {
-    "bun": "bin/bun",
-    "bunx": "bin/bun"
-  },
-  "repository": "https://github.com/oven-sh/bun",
-  "scripts": {
-    "postinstall": "node install.js"
-  },
-  "optionalDependencies": {
-    "@oven/bun-darwin-aarch64": "0.5.3",
-    "@oven/bun-darwin-x64": "0.5.3",
-    "@oven/bun-darwin-x64-baseline": "0.5.3",
-    "@oven/bun-linux-aarch64": "0.5.3",
-    "@oven/bun-linux-x64": "0.5.3",
-    "@oven/bun-linux-x64-baseline": "0.5.3"
-  },
-  "os": [
-    "darwin",
-    "linux"
-  ],
-  "cpu": [
-    "arm64",
-    "x64"
-  ]
-}
diff --git a/packages/bun-release/package.json b/packages/bun-release/package.json
index c0ed4bad38..1c4719ec60 100644
--- a/packages/bun-release/package.json
+++ b/packages/bun-release/package.json
@@ -9,7 +9,7 @@
   },
   "devDependencies": {
     "@octokit/types": "^8.1.1",
-    "bun-types": "^0.4.0",
+    "bun-types": "^1.1.0",
     "prettier": "^2.8.2"
   },
   "scripts": {
diff --git a/packages/bun-release/scripts/npm-exec.ts b/packages/bun-release/scripts/npm-exec.ts
index 517f296cea..5938f43837 100644
--- a/packages/bun-release/scripts/npm-exec.ts
+++ b/packages/bun-release/scripts/npm-exec.ts
@@ -1,4 +1,4 @@
-import { importBun } from "../src/npm/install";
+import { importBun, optimizeBun } from "../src/npm/install";
 import { execFileSync } from "child_process";
 
 importBun()
diff --git a/packages/bun-release/scripts/upload-npm.ts b/packages/bun-release/scripts/upload-npm.ts
index 3cd8cd9d5d..fbb99afb79 100644
--- a/packages/bun-release/scripts/upload-npm.ts
+++ b/packages/bun-release/scripts/upload-npm.ts
@@ -1,4 +1,8 @@
 import { join, copy, exists, chmod, write, writeJson } from "../src/fs";
+import { mkdtemp } from "fs/promises";
+import { rmSync, mkdirSync } from "fs";
+import { tmpdir } from "os";
+import { dirname } from "path";
 import { fetch } from "../src/fetch";
 import { spawn } from "../src/spawn";
 import type { Platform } from "../src/platform";
@@ -10,41 +14,51 @@ import { buildSync, formatMessagesSync } from "esbuild";
 import type { JSZipObject } from "jszip";
 import { loadAsync } from "jszip";
 import { debug, log, error } from "../src/console";
+import { expect } from "bun:test";
 
 const module = "bun";
 const owner = "@oven";
-let version: string;
 
 const [tag, action] = process.argv.slice(2);
 
-await build(tag);
+const release = await getRelease(tag);
+const version = await getSemver(release.tag_name);
+
+if (action !== "test-only") await build();
+
 if (action === "publish") {
   await publish();
 } else if (action === "dry-run") {
   await publish(true);
+} else if (action === "test") {
+  await publish(true);
+  await test();
+} else if (action === "test-only") {
+  await test();
 } else if (action) {
   throw new Error(`Unknown action: ${action}`);
 }
 process.exit(0); // HACK
 
-async function build(tag?: string): Promise<void> {
-  const release = await getRelease(tag);
-  version = await getSemver(release.tag_name);
+async function build(): Promise<void> {
   await buildRootModule();
   for (const platform of platforms) {
+    if (action !== "publish" && (platform.os !== process.platform || platform.arch !== process.arch)) continue;
     await buildModule(release, platform);
   }
 }
 
 async function publish(dryRun?: boolean): Promise<void> {
-  const modules = platforms.map(({ bin }) => `${owner}/${bin}`);
+  const modules = platforms
+    .filter(({ os, arch }) => action === "publish" || (os === process.platform && arch === process.arch))
+    .map(({ bin }) => `${owner}/${bin}`);
   modules.push(module);
   for (const module of modules) {
     publishModule(module, dryRun);
   }
 }
 
-async function buildRootModule() {
+async function buildRootModule(dryRun?: boolean) {
   log("Building:", `${module}@${version}`);
   const cwd = join("npm", module);
   const define = {
@@ -54,28 +68,53 @@ async function buildRootModule() {
   };
   bundle(join("scripts", "npm-postinstall.ts"), join(cwd, "install.js"), {
     define,
-  });
-  bundle(join("scripts", "npm-exec.ts"), join(cwd, "bin", "bun"), {
-    define,
     banner: {
-      js: "#!/usr/bin/env node",
+      js: "// Source code: https://github.com/oven-sh/bun/blob/main/packages/bun-release/scripts/npm-postinstall.ts",
     },
   });
+  write(join(cwd, "bin", "bun.exe"), "");
+  write(
+    join(cwd, "bin", "README.txt"),
+    `The 'bun.exe' file is a placeholder for the binary file, which
+is replaced by Bun's 'postinstall' script. For this to work, make
+sure that you do not use --ignore-scripts while installing.
+
+The postinstall script is responsible for linking the binary file
+directly into 'node_modules/.bin' and avoiding a Node.js wrapper
+script being called on every invocation of 'bun'. If this wasn't
+done, Bun would seem to be slower than Node.js, because it would
+be executing a copy of Node.js every time!
+
+Unfortunately, it is not possible to fix all cases on all platforms
+without *requiring* a postinstall script.
+`,
+  );
   const os = [...new Set(platforms.map(({ os }) => os))];
   const cpu = [...new Set(platforms.map(({ arch }) => arch))];
   writeJson(join(cwd, "package.json"), {
     name: module,
+    description: "Bun is a fast all-in-one JavaScript runtime.",
     version: version,
     scripts: {
       postinstall: "node install.js",
     },
-    optionalDependencies: Object.fromEntries(platforms.map(({ bin }) => [`${owner}/${bin}`, version])),
+    optionalDependencies: Object.fromEntries(
+      platforms.map(({ bin }) => [
+        `${owner}/${bin}`,
+        dryRun ? `file:./oven-${bin.replaceAll("/", "-") + "-" + version + ".tgz"}` : version,
+      ]),
+    ),
     bin: {
-      bun: "bin/bun",
-      bunx: "bin/bun",
+      bun: "bin/bun.exe",
+      bunx: "bin/bun.exe",
     },
     os,
     cpu,
+    keywords: ["bun", "bun.js", "node", "node.js", "runtime", "bundler", "transpiler", "typescript"],
+    homepage: "https://bun.sh",
+    bugs: "https://github.com/oven-sh/issues",
+    license: "MIT",
+    repository: "https://github.com/oven-sh/bun",
   });
   if (exists(".npmrc")) {
     copy(".npmrc", join(cwd, ".npmrc"));
@@ -95,11 +134,17 @@ async function buildModule(
   }
   const bun = await extractFromZip(asset.browser_download_url, `${bin}/bun`);
   const cwd = join("npm", module);
+  mkdirSync(dirname(join(cwd, exe)), { recursive: true });
   write(join(cwd, exe), await bun.async("arraybuffer"));
   chmod(join(cwd, exe), 0o755);
   writeJson(join(cwd, "package.json"), {
     name: module,
     version: version,
+    description: "This is the macOS arm64 binary for Bun, a fast all-in-one JavaScript runtime.",
+    homepage: "https://bun.sh",
+    bugs: "https://github.com/oven-sh/issues",
+    license: "MIT",
+    repository: "https://github.com/oven-sh/bun",
     preferUnplugged: true,
     os: [os],
     cpu: [arch],
@@ -111,22 +156,33 @@ async function buildModule(
 
 function publishModule(name: string, dryRun?: boolean): void {
   log(dryRun ? "Dry-run Publishing:" : "Publishing:", `${name}@${version}`);
-  const { exitCode, stdout, stderr } = spawn(
-    "npm",
-    [
-      "publish",
-      "--access",
-      "public",
-      "--tag",
-      version.includes("canary") ? "canary" : "latest",
-      ...(dryRun ? ["--dry-run"] : []),
-    ],
-    {
-      cwd: join("npm", name),
-    },
-  );
-  if (exitCode === 0) {
+  if (!dryRun) {
+    const { exitCode, stdout, stderr } = spawn(
+      "npm",
+      [
+        "publish",
+        "--access",
+        "public",
+        "--tag",
+        version.includes("canary") ? "canary" : "latest",
+        ...(dryRun ? ["--dry-run"] : []),
+      ],
+      {
+        cwd: join("npm", name),
+      },
+    );
     error(stderr || stdout);
+    if (exitCode !== 0) {
+      throw new Error("npm publish failed with code " + exitCode);
+    }
+  } else {
+    const { exitCode, stdout, stderr } = spawn("npm", ["pack"], {
+      cwd: join("npm", name),
+    });
+    error(stderr || stdout);
+    if (exitCode !== 0) {
+      throw new Error("npm pack failed with code " + exitCode);
+    }
   }
 }
 
@@ -162,3 +218,86 @@ function bundle(src: string, dst: string, options: BuildOptions = {}): void {
     throw new Error(messages.join("\n"));
   }
 }
+
+async function test() {
+  const root = await mkdtemp(join(tmpdir(), "bun-release-test-"));
+  const $ = new Bun.$.Shell().cwd(root);
+
+  for (const platform of platforms) {
+    if (platform.os !== process.platform) continue;
+    if (platform.arch !== process.arch) continue;
+    copy(
+      join(
+        import.meta.dir,
+        "../npm/@oven/",
+        platform.bin,
+        "oven-" + platform.bin.replaceAll("/", "-") + `-${version}.tgz`,
+      ),
+      join(root, `${platform.bin}-${version}.tgz`),
+    );
+  }
+
+  copy(join(import.meta.dir, "../npm", "bun", "bun-" + version + ".tgz"), join(root, "bun-" + version + ".tgz"));
+
+  console.log(root);
+  for (const [install, exec] of [
+    ["npm i", "npm exec"],
+    ["yarn set version berry; yarn add", "yarn"],
+    ["yarn set version latest; yarn add", "yarn"],
+    ["pnpm i", "pnpm"],
+    ["bun i", "bun run"],
+  ]) {
+    rmSync(join(root, "node_modules"), { recursive: true, force: true });
+    rmSync(join(root, "package-lock.json"), { recursive: true, force: true });
+    rmSync(join(root, "package.json"), { recursive: true, force: true });
+    rmSync(join(root, "pnpm-lock.yaml"), { recursive: true, force: true });
+    rmSync(join(root, "yarn.lock"), { recursive: true, force: true });
+    writeJson(join(root, "package.json"), {
+      name: "bun-release-test",
+    });
+
+    console.log("Testing", install + " bun");
+    await $`${{ raw: install }} ./bun-${version}.tgz`;
+
+    console.log("Running " + exec + " bun");
+
+    // let output = await $`${{
+    //   raw: exec,
+    // }} bun -- -e "console.log(JSON.stringify([Bun.version, process.platform, process.arch, process.execPath]))"`.text();
+    const split = exec.split(" ");
+    let {
+      stdout: output,
+      stderr,
+      exitCode,
+    } = spawn(
+      split[0],
+      [
+        ...split.slice(1),
+        "--",
+        "bun",
+        "-e",
+        "console.log(JSON.stringify([Bun.version, process.platform, process.arch, process.execPath]))",
+      ],
+      {
+        cwd: root,
+      },
+    );
+    if (exitCode !== 0) {
+      console.error(stderr);
+      throw new Error("Failed to run " + exec + " bun, exit code: " + exitCode);
+    }
+
+    try {
+      output = JSON.parse(output);
+    } catch (e) {
+      console.log({ output });
+      throw e;
+    }
+
+    expect(output[0]).toBe(version);
+    expect(output[1]).toBe(process.platform);
+    expect(output[2]).toBe(process.arch);
+    expect(output[3]).toStartWith(root);
+    expect(output[3]).toInclude("bun");
+  }
+}
diff --git a/packages/bun-release/src/npm/install.ts b/packages/bun-release/src/npm/install.ts
index fcb829c70f..37ed2c3165 100644
--- a/packages/bun-release/src/npm/install.ts
+++ b/packages/bun-release/src/npm/install.ts
@@ -121,16 +121,9 @@ async function downloadBun(platform: Platform, dst: string): Promise<void> {
 }
 
 export function optimizeBun(path: string): void {
-  const installScript =
-    os === "win32" ? 'powershell -c "irm bun.sh/install.ps1 | iex"' : "curl -fsSL https://bun.sh/install | bash";
-  const { npm_config_user_agent } = process.env;
-  if (npm_config_user_agent && /\byarn\//.test(npm_config_user_agent)) {
-    throw new Error(
-      `Yarn does not support bun, because it does not allow linking to binaries. To use bun, install using the following command: ${installScript}`,
-    );
-  }
+  const installScript = os === "win32" ? 'powershell -c "irm bun.sh/install.ps1 | iex"' : "curl -fsSL https://bun.sh/install | bash";
   try {
-    rename(path, join(__dirname, "bin", "bun"));
+    rename(path, join(__dirname, "bin", "bun.exe"));
     return;
   } catch (error) {
     debug("optimizeBun failed", error);
diff --git a/packages/bun-release/src/platform.ts b/packages/bun-release/src/platform.ts
index e38de526cf..fbe4d9d373 100644
--- a/packages/bun-release/src/platform.ts
+++ b/packages/bun-release/src/platform.ts
@@ -106,6 +106,15 @@ function isRosetta2(): boolean {
 }
 
 function isWindowsAVX2(): boolean {
-  // TODO: Implement AVX2 detection on Windows
-  return false;
+  try {
+    return (
+      spawn("powershell", [
+        "-c",
+        `(Add-Type -MemberDefinition '[DllImport("kernel32.dll")] public static extern bool IsProcessorFeaturePresent(int ProcessorFeature);' -Name 'Kernel32' -Namespace 'Win32' -PassThru)::IsProcessorFeaturePresent(40);`,
+      ]).stdout == "True"
+    );
+  } catch (error) {
+    debug("isWindowsAVX2 failed", error);
+    return false;
+  }
 }