diff --git a/.project-docs/30-worklog/tasks/20260819-disable-http2-package-b84c7e.md b/.project-docs/30-worklog/tasks/20260819-disable-http2-package-b84c7e.md
new file mode 100644
index 0000000..3eb9cea
--- /dev/null
+++ b/.project-docs/30-worklog/tasks/20260819-disable-http2-package-b84c7e.md
@@ -0,0 +1,56 @@
+# Task: Build HTTP2-disabled diagnostic package
+
+## Identity
+
+- Task ID: 20260819-disable-http2-package-b84c7e
+- Mode: Feature
+- Branch: codex/20260819-disable-http2-package-b84c7e-disable-http2-package
+- Worktree: D:\mk-disable-http2-b84c7e
+- Base commit: 9ff79e96813ebadade0aecb8f407edf5aee0144a
+- Owner: codex-root
+- Status: Completed
+
+## Scope
+
+- Build a Windows x64 diagnostic installer from local `main` base `9ff79e9` with Chromium HTTP/2 disabled globally so the user can A/B the observed request fan-out stall against HTTP/1.1.
+- Keep the source change limited to Electron Main startup and a focused ordering regression test; do not change Quote, authentication, retry, timeout, Renderer, or server behavior.
+
+## Intent And Constraints
+
+- Apply Chromium's `disable-http2` command-line switch before `app.whenReady()`, window creation, or network initialization.
+- Treat the installer as diagnostic evidence, not a permanent protocol policy or a fix for the independent unbounded shared authentication flights.
+- Build with the exact pnpm version pinned by `packageManager`; do not commit generated packages, downloaded runtimes, caches, or secrets.
+- Keep all work in `D:\mk-disable-http2-b84c7e`; the main worktree remains owned by a superseded packaging record and is not modified.
+- The user previously prohibited sub-agents; implementation and validation are performed directly without delegated or reviewer agents.
+
+## Outcome
+
+- Added `app.commandLine.appendSwitch('disable-http2')` at Electron Main bootstrap, before the single-instance lock and `app.whenReady()`.
+- Added a focused regression test that guards the switch and its startup ordering.
+- Built the Windows x64 diagnostic installer `release/Makelore-2.0.0-win-x64.exe` without installing it or interrupting the user's running client.
+- The package reuses the installed client's repository-validated, versioned Learning Player (`htmlSha256` `748d6d7c74d9d0ba444e0c051a50010f7070e7d6e46442b1e60f1e2be80fd020`) so the transport switch remains the intended A/B variable.
+
+## Verification
+
+- Red test: `pnpm exec vitest run tests/unit/http2-diagnostic-bootstrap.test.ts --reporter=verbose` failed before implementation because the switch was absent.
+- Green test: the same focused Vitest command passed after implementation (1 test).
+- `pnpm run typecheck` passed.
+- `pnpm exec eslint electron/main/index.ts tests/unit/http2-diagnostic-bootstrap.test.ts` passed.
+- `pnpm run build:vite` passed; only pre-existing Vite chunk/dynamic-import warnings were emitted.
+- Packaged Main inspection found `disable-http2` in `dist-electron/main/index-Cn0aQm66.js` at byte offset 500965, before `requestSingleInstanceLock` at 501868 and `whenReady` at 511598.
+- `pnpm run verify:publish-runtime` passed (`npm 11.6.2`).
+- `pnpm run verify:artifact:win -- --allow-dirty --installer .\\release\\Makelore-2.0.0-win-x64.exe` passed for Electron 43.4.0, Node 24.18.1, OpenCode 1.18.9, Python, uv 0.10.0, npm 11.6.2, native modules, and Unicode-copy proof.
+- Packaged `package.json` reports version `2.0.0`; installer FileVersion and ProductVersion are both `2.0.0`.
+- Installer size: 302,025,645 bytes; SHA-256: `1C4E4E67F29A58E81705CA258E171200576BE41B313B4CD794D49CD296B479EE`.
+- Authenticode status is `NotSigned`, consistent with the local unsigned packaging configuration.
+- `git diff --check` passed.
+
+## Follow-ups
+
+- The user should exit the currently running Makelore instance, install the diagnostic package, reproduce the same Quote PATCH flow, and compare whether global pending requests and `net::ERR_HTTP2_PROTOCOL_ERROR` disappear.
+- If the stall remains under forced HTTP/1.1, resume diagnosis at the shared authentication/request single-flight path rather than treating HTTP/2 as the root cause.
+- If the stall disappears, capture server/proxy and Chromium NetLog evidence before deciding whether to keep a protocol workaround or repair the HTTP/2 path.
+
+## Promotion Candidates
+
+- Keep the startup switch temporary until the A/B result is known; do not promote it as a permanent release policy without evidence.
diff --git a/electron/main/index.ts b/electron/main/index.ts
index e5cd58a..8482bd8 100644
--- a/electron/main/index.ts
+++ b/electron/main/index.ts
@@ -95,6 +95,9 @@ import {
 import { WorksSquareDesignWorkspace } from '../image-workspace/works-square-workspace';
 import type { DesignWorkspaceModule } from '../image-workspace/module';
 
+// Diagnostic package: force Chromium networking onto HTTP/1.1 for transport A/B testing.
+app.commandLine.appendSwitch('disable-http2');
+
 const WINDOWS_APP_USER_MODEL_ID = 'app.niancode.desktop';
 const isE2EMode = process.env.NIANCODE_E2E === '1';
 const requestedUserDataDir = process.env.NIANCODE_USER_DATA_DIR?.trim();
diff --git a/tests/unit/http2-diagnostic-bootstrap.test.ts b/tests/unit/http2-diagnostic-bootstrap.test.ts
new file mode 100644
index 0000000..d233f63
--- /dev/null
+++ b/tests/unit/http2-diagnostic-bootstrap.test.ts
@@ -0,0 +1,16 @@
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import { describe, expect, it } from 'vitest';
+
+describe('HTTP/1.1 diagnostic bootstrap', () => {
+  it('disables HTTP/2 before Electron startup and network initialization', () => {
+    const source = readFileSync(resolve(process.cwd(), 'electron/main/index.ts'), 'utf8');
+    const disableHttp2 = source.indexOf("app.commandLine.appendSwitch('disable-http2')");
+    const singleInstanceLock = source.indexOf('app.requestSingleInstanceLock()');
+    const ready = source.indexOf('app.whenReady()');
+
+    expect(disableHttp2).toBeGreaterThan(-1);
+    expect(disableHttp2).toBeLessThan(singleInstanceLock);
+    expect(disableHttp2).toBeLessThan(ready);
+  });
+});