diff --git a/apps/server/src/cloud/pinnedRuntime.test.ts b/apps/server/src/cloud/pinnedRuntime.test.ts
index 0c016a504c9b4..9fd493d15690b 100644
--- a/apps/server/src/cloud/pinnedRuntime.test.ts
+++ b/apps/server/src/cloud/pinnedRuntime.test.ts
@@ -285,6 +285,80 @@ it.layer(NodeServices.layer)("ensurePinnedRuntimeInstalled", (it) => {
     }),
   );
 
+  it.effect("retries a release archive whose body stalls after the host answered", () =>
+    Effect.gen(function* () {
+      const fs = yield* FileSystem.FileSystem;
+      const path = yield* Path.Path;
+      const baseDir = yield* fs.makeTempDirectoryScoped({ prefix: "t3-pinned-retry-stall-" });
+      const checksums = yield* validChecksums;
+      let archiveRequests = 0;
+      const archiveRequested = yield* Deferred.make<void>();
+      const install = yield* ensurePinnedRuntimeInstalled({
+        baseDir,
+        version,
+        fs,
+        path,
+        platform: "linux",
+        arch: "x64",
+        httpClient: HttpClient.make((request) => {
+          const isChecksums = request.url.endsWith("/SHA256SUMS");
+          const response = HttpClientResponse.fromWeb(
+            request,
+            new Response(isChecksums ? checksums : archiveBytes),
+          );
+          if (isChecksums || ++archiveRequests > 1) return Effect.succeed(response);
+          const stalledBody = Stream.concat(Stream.make(archiveBytes.slice(0, 4)), Stream.never);
+          Deferred.doneUnsafe(archiveRequested, Effect.void);
+          return Effect.sleep("1 second").pipe(
+            Effect.as<HttpClientResponse.HttpClientResponse>(
+              Object.create(response, { stream: { value: stalledBody } }),
+            ),
+          );
+        }),
+        runner: extractingRunner(fs, path),
+        validate: () => Effect.void,
+      }).pipe(Effect.forkScoped);
+      yield* Deferred.await(archiveRequested);
+      // 1 s to answer, the 1 min stall timeout, then the 2 s retry wait.
+      yield* TestClock.adjust(Duration.seconds(63));
+      const paths = yield* Fiber.join(install);
+      assert.equal(yield* fs.readFileString(paths.sentinelPath), `${version}\n`);
+      assert.equal(archiveRequests, 2);
+    }),
+  );
+
+  it.effect("fails at once when the release host never answers", () =>
+    Effect.gen(function* () {
+      const fs = yield* FileSystem.FileSystem;
+      const path = yield* Path.Path;
+      const baseDir = yield* fs.makeTempDirectoryScoped({ prefix: "t3-pinned-no-answer-" });
+      let requests = 0;
+      const requested = yield* Deferred.make<void>();
+      const install = yield* ensurePinnedRuntimeInstalled({
+        baseDir,
+        version,
+        fs,
+        path,
+        platform: "linux",
+        arch: "x64",
+        httpClient: HttpClient.make(() => {
+          requests += 1;
+          Deferred.doneUnsafe(requested, Effect.void);
+          return Effect.never;
+        }),
+        runner: extractingRunner(fs, path),
+        validate: () => Effect.die("must not validate without a download"),
+      }).pipe(Effect.forkScoped);
+      yield* Deferred.await(requested);
+      // Long enough for a retry to have started had the no-answer timeout been retried.
+      yield* TestClock.adjust(Duration.minutes(2));
+      assert.equal(requests, 1);
+      const error = yield* Fiber.join(install).pipe(Effect.flip);
+      assert.instanceOf(error, PinnedRuntimeInstallError);
+      assert.equal(error.step, "downloading the t3 release checksums (timed out)");
+    }),
+  );
+
   it.effect("fails at once when the release host cannot be reached", () =>
     Effect.gen(function* () {
       const fs = yield* FileSystem.FileSystem;
diff --git a/apps/server/src/cloud/pinnedRuntime.ts b/apps/server/src/cloud/pinnedRuntime.ts
index 5f7e170530d79..e1f7514e5b5cd 100644
--- a/apps/server/src/cloud/pinnedRuntime.ts
+++ b/apps/server/src/cloud/pinnedRuntime.ts
@@ -123,11 +123,18 @@ interface PinnedRuntimeInstallInput {
 // GitHub release downloads intermittently answer 5xx during incidents; a retry usually lands.
 const DOWNLOAD_RETRY = { times: 3, schedule: Schedule.exponential("2 seconds") } as const;
 
+/** The release host answered, then sent no body bytes for the stall timeout. */
+class ReleaseDownloadStalledError extends Schema.TaggedError<ReleaseDownloadStalledError>()(
+  "ReleaseDownloadStalledError",
+  {},
+) {}
+
 const isTransientDownloadFailure = (
-  error: HttpClientError.HttpClientError | Cause.TimeoutError,
+  error: HttpClientError.HttpClientError | Cause.TimeoutError | ReleaseDownloadStalledError,
 ): boolean => {
-  // No answer or a stall means the host cannot reach the release source; retrying only delays that.
+  // No answer means the host cannot reach the release source; retrying only delays that.
   if (error._tag === "TimeoutError") return false;
+  if (error._tag === "ReleaseDownloadStalledError") return true;
   // Body bytes are read raw, so a DecodeError is a body that failed after the host answered.
   if (error.reason._tag === "DecodeError") return true;
   const status = error.response?.status;
@@ -154,7 +161,7 @@ const fetchReleaseAsset = Effect.fn("cloud.pinned_runtime.fetch_release_asset")(
         const chunks = yield* response.stream.pipe(
           Stream.timeoutOrElse({
             duration: PINNED_RUNTIME_DOWNLOAD_STALL_TIMEOUT,
-            orElse: () => Stream.fail(new Cause.TimeoutError()),
+            orElse: () => Stream.fail(new ReleaseDownloadStalledError()),
           }),
           Stream.tap((chunk) =>
             Effect.sync(() => {
@@ -180,7 +187,10 @@ const fetchReleaseAsset = Effect.fn("cloud.pinned_runtime.fetch_release_asset")(
     Effect.mapError(
       (cause) =>
         new PinnedRuntimeInstallError({
-          step: cause._tag === "TimeoutError" ? `${step} (timed out)` : step,
+          step:
+            cause._tag === "TimeoutError" || cause._tag === "ReleaseDownloadStalledError"
+              ? `${step} (timed out)`
+              : step,
           httpStatus:
             HttpClientError.isHttpClientError(cause) && cause.reason._tag === "StatusCodeError"
               ? cause.reason.response.status