diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 88a678a..831f55c 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -22,7 +22,7 @@ jobs:
         with:
           node-version: 22
 
-      - uses: mlugg/setup-zig@v2
+      - uses: mlugg/setup-zig@v2.0.5
 
       - name: Install binaryen
         run: |
diff --git a/src/utils.ts b/src/utils.ts
index 0874949..29348c5 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,7 +1,7 @@
 // @ts-ignore
 import zigTarGz from "../zig-out/zig.tar.gz?inline";
 import { untar } from "@andrewbranch/untar.js";
-import { Directory, File } from "@bjorn3/browser_wasi_shim";
+import { Directory, File, ConsoleStdout, wasi as wasi_defs } from "@bjorn3/browser_wasi_shim";
 
 export async function getLatestZigArchive() {
     const ds = new DecompressionStream("gzip");
@@ -43,3 +43,14 @@ function convert(node: TreeNode): Directory {
         })
     )
 }
+
+export function stderrOutput(): ConsoleStdout {
+    const dec = new TextDecoder("utf-8", { fatal: false });
+    const stderr = new ConsoleStdout((buffer) => {
+        postMessage({ stderr: dec.decode(buffer, { stream: true }) });
+    });
+    stderr.fd_pwrite = (data, offset) => {
+        return { ret: wasi_defs.ERRNO_SPIPE, nwritten: 0 };
+    }
+    return stderr;
+}
diff --git a/src/workers/runner.ts b/src/workers/runner.ts
index a46b55e..52973c3 100644
--- a/src/workers/runner.ts
+++ b/src/workers/runner.ts
@@ -1,13 +1,7 @@
 // Runs compiled Zig code
 
-import { WASI, PreopenDirectory, OpenFile, File, ConsoleStdout } from "@bjorn3/browser_wasi_shim";
-
-function stderrOutput(): ConsoleStdout {
-    const dec = new TextDecoder("utf-8", { fatal: false });
-    return new ConsoleStdout((buffer) => {
-        postMessage({ stderr: dec.decode(buffer, { stream: true }) });
-    });
-}
+import { WASI, PreopenDirectory, OpenFile, File } from "@bjorn3/browser_wasi_shim";
+import { stderrOutput } from "../utils";
 
 async function run(wasmData: Uint8Array) {
     let args = ["main.wasm"];
diff --git a/src/workers/zig.ts b/src/workers/zig.ts
index 4c89afe..f4905c4 100644
--- a/src/workers/zig.ts
+++ b/src/workers/zig.ts
@@ -1,15 +1,8 @@
-import { WASI, PreopenDirectory, Fd, File, ConsoleStdout, OpenFile, Inode } from "@bjorn3/browser_wasi_shim";
-import { getLatestZigArchive } from "../utils";
+import { WASI, PreopenDirectory, Fd, File, OpenFile, Inode } from "@bjorn3/browser_wasi_shim";
+import { getLatestZigArchive, stderrOutput } from "../utils";
 // @ts-ignore
 import zigWasm from "../../zig-out/bin/zig.wasm?url";
 
-function stderrOutput(): ConsoleStdout {
-    const dec = new TextDecoder("utf-8", { fatal: false });
-    return new ConsoleStdout((buffer) => {
-        postMessage({ stderr: dec.decode(buffer, { stream: true }) });
-    });
-}
-
 let currentlyRunning = false;
 async function run(source: string) {
     if (currentlyRunning) return;