diff --git a/packages/cli/src/commands/serve.ts b/packages/cli/src/commands/serve.ts
index e24a5526a3..4d0fc10c65 100644
--- a/packages/cli/src/commands/serve.ts
+++ b/packages/cli/src/commands/serve.ts
@@ -86,29 +86,33 @@ async function downloadWebDist(version: string, targetDir: string): Promise<void
   log.info({ version, targetDir }, 'web_dist.download_started');
   console.log(`Web UI not found locally — downloading from release v${version}...`);
 
-  // Download checksums
-  const checksumsRes = await fetch(checksumsUrl).catch((err: unknown) => {
-    throw new Error(
-      `Network error fetching checksums from ${checksumsUrl}: ${(err as Error).message}`
-    );
-  });
+  // Download checksums and tarball in parallel
+  console.log(`Downloading ${tarballUrl}...`);
+  const [checksumsRes, tarballRes] = await Promise.all([
+    fetch(checksumsUrl).catch((err: unknown) => {
+      throw new Error(
+        `Network error fetching checksums from ${checksumsUrl}: ${(err as Error).message}`
+      );
+    }),
+    fetch(tarballUrl).catch((err: unknown) => {
+      throw new Error(
+        `Network error fetching tarball from ${tarballUrl}: ${(err as Error).message}`
+      );
+    }),
+  ]);
   if (!checksumsRes.ok) {
     throw new Error(
       `Failed to download checksums: ${checksumsRes.status} ${checksumsRes.statusText}`
     );
   }
-  const checksumsText = await checksumsRes.text();
-  const expectedHash = parseChecksum(checksumsText, 'archon-web.tar.gz');
-
-  // Download tarball
-  console.log(`Downloading ${tarballUrl}...`);
-  const tarballRes = await fetch(tarballUrl).catch((err: unknown) => {
-    throw new Error(`Network error fetching tarball from ${tarballUrl}: ${(err as Error).message}`);
-  });
   if (!tarballRes.ok) {
     throw new Error(`Failed to download web UI: ${tarballRes.status} ${tarballRes.statusText}`);
   }
-  const tarballBuffer = await tarballRes.arrayBuffer();
+  const [checksumsText, tarballBuffer] = await Promise.all([
+    checksumsRes.text(),
+    tarballRes.arrayBuffer(),
+  ]);
+  const expectedHash = parseChecksum(checksumsText, 'archon-web.tar.gz');
 
   // Verify checksum
   const hasher = new Bun.CryptoHasher('sha256');
diff --git a/packages/cli/src/commands/setup.ts b/packages/cli/src/commands/setup.ts
index b94529cd4c..cc0b138a61 100644
--- a/packages/cli/src/commands/setup.ts
+++ b/packages/cli/src/commands/setup.ts
@@ -1203,7 +1203,7 @@ export function copyArchonSkill(targetPath: string): void {
 function trySpawn(
   command: string,
   args: string[],
-  options: { detached: boolean; stdio: 'ignore'; shell?: boolean }
+  options: { detached: boolean; stdio: 'ignore' }
 ): boolean {
   try {
     const child: ChildProcess = spawn(command, args, options);
@@ -1238,7 +1238,6 @@ function spawnWindowsTerminal(repoPath: string): SpawnResult {
     trySpawn('cmd.exe', ['/c', 'start', '""', '/D', repoPath, 'cmd', '/k', 'archon setup'], {
       detached: true,
       stdio: 'ignore',
-      shell: true,
     })
   ) {
     return { success: true };
diff --git a/packages/paths/src/update-check.ts b/packages/paths/src/update-check.ts
index 46652eb0d8..1e7da7dd41 100644
--- a/packages/paths/src/update-check.ts
+++ b/packages/paths/src/update-check.ts
@@ -1,5 +1,5 @@
 import { join } from 'path';
-import { existsSync, readFileSync, writeFileSync, mkdirSync } from 'fs';
+import { readFileSync, writeFileSync, mkdirSync } from 'fs';
 import { getArchonHome } from './archon-paths';
 import { createLogger } from './logger';
 
@@ -30,7 +30,6 @@ function getCachePath(): string {
 function readCache(): UpdateCheckCache | null {
   const cachePath = getCachePath();
   try {
-    if (!existsSync(cachePath)) return null;
     const raw = readFileSync(cachePath, 'utf-8');
     const data = JSON.parse(raw) as UpdateCheckCache;
     if (!data.latestVersion || !data.releaseUrl || typeof data.checkedAt !== 'number') {