stjanovitz/tilefinch

An experimental web browser for the Sony PSP (333 MHz, 64 MB): a from-scratch layout engine, JavaScript, and hardware-assisted video, all running on the handheld itself.

Wikipedia at PSP resolution	360p video playback

Reader mode	Dark mode
WebGL games	Danzeff text entry

I picked up my PSP for the first time in about a decade and wanted an excuse to find out three things: how far the machine could be pushed, how much of the modern web could run in a setting this constrained, and what today's coding agents are capable of. A web browser tests all three.

Detailed performance and memory experiment ledgers are kept locally and in the private development archive, not in this public repository. Public engineering documentation describes the current contracts and reproducible checks.

• A PSP that runs homebrew (custom firmware) and has the 64 MB memory mode:
  • PSP-3000: the tested model. Everything claimed on this page ran on it.
  • PSP-2000 and PSP Go: same memory mode, expected to work, not yet qualified.
  • PSP-1000: not supported. It has 32 MB of RAM, and most sites need more.
  • PSP-E1000 (Street): has the memory but no Wi-Fi, so only the offline library would work. Not a sensible target.
• About 20 MB free on the Memory Stick for everyday browsing and updates.
  • Optional glyph packs take about 1 MB each; the color-emoji pack takes about 5 MB. Besides the selected language pack, Tilefinch can attach up to two other installed packs when a page uses their scripts. A page that needs a pack you have not installed offers it in a notice you can ignore; installing from that notice first shows the signed download size and asks again.
  • Installing the optional voice model needs about 19 MB more while the verified download and the new copy coexist. Allow 40 MB free if you want voice recognition.
• A Wi-Fi network the PSP can join. With the latest ARK-4 custom firmware, WPA2 works; otherwise the PSP joins only WPA (TKIP) or open networks, a limit of its hardware era. Most routers can offer a WPA/TKIP guest network. Save the connection in the PSP's own Network Settings first.

1. Download the PSP install .zip from the latest Tilefinch release.
2. Extract it and copy the whole TILEFINCH folder to PSP/GAME/ on the Memory Stick. The launcher should end up at PSP/GAME/TILEFINCH/EBOOT.PBP, with slot-a, slot-b, data, and NOTICES beside it.
3. Safely disconnect the PSP, then start Tilefinch from Game → Memory Stick.
4. If you have not already, save a Wi-Fi connection in the PSP's Network Settings. Tilefinch uses connection profile 1 unless you choose another in Settings → Device & storage.

The .tfum and .tfup files on the release page are for Tilefinch's signed in-app updater, not for manual installation. Optional language, emoji, and voice components are installed from their Settings screens.

ARK-4 users can make Network → Internet Browser open Tilefinch. This is an optional VSH plugin: it does not modify the PSP firmware or flash0, polls nothing in the background, and writes nothing to the Memory Stick.

1. Install Tilefinch normally at PSP/GAME/TILEFINCH/.
2. Copy TILEFINCH/OPTIONAL/tilefinch_xmb.prx from the install archive to ms0:/SEPLUGINS/tilefinch_xmb.prx.
3. In ARK's Custom Launcher or Plugin Manager, install or enable the plugin for the VSH (XMB) runlevel.
4. Restart VSH or reboot the PSP.

The equivalent manual line in ARK's PLUGINS.TXT is:

vsh, ms0:/SEPLUGINS/tilefinch_xmb.prx, on

On a PSP Go using internal storage, use ef0: in both paths.

• Hold L while opening the Internet Browser icon to get Sony's browser. Because the redirect uses L for this, Tilefinch's previous-version safe start is available only when you launch Tilefinch from Game → Memory Stick.
• If Tilefinch is missing or the handoff fails, Sony's browser stays open.
• To restore the original behavior, disable the plugin in ARK's Plugin Manager and restart VSH.

Tilefinch still runs as an ordinary homebrew application, not as code inside VSH, so leaving it reloads the XMB and may show the usual Sony or ARK startup screen. After replacing the plugin file itself, power the PSP off completely and cold-boot it: Restart VSH can keep the previous NO_STOP handler in memory. The redirect starts Tilefinch's stable root launcher, so signed updates, trial boots, and automatic rollback work as usual. ARK-4's plugin documentation describes its Plugin Manager and PLUGINS.TXT formats.

Official releases do not redistribute the custom H.264 and AAC decoder. Compatible Baseline/Main MP4 and HLS, live streams included, keep using the PSP's firmware. To add the 240p High-profile path, build the add-on from its pinned upstream source by following Optional PSP software decoder, then copy its three files to PSP/GAME/TILEFINCH/components/swdec/.

That directory sits outside both app slots, so signed updates keep the add-on. Update metadata records the decoder ABI: if a future update changes it, the update screen says Decoder rebuild needed. When a page needs the add-on and it is missing or incompatible, the player points to these build instructions rather than reporting a generic video failure.

Type a URL in the address bar to go there, or anything else to search.

The user guide covers everyday use in detail:

• Typing with the PSP keyboard or the faster Danzeff layout, with completion from your bookmarks and history.
• Find in page from Menu → Page tools.
• Reader mode, Basic view for pages whose scripts fail, and the offline library of saved articles and video downloads.
• Games and page controls: handing the buttons to a page's Gamepad API, fullscreen, game audio, and direct multiplayer.
• Screenshots, what Tilefinch offers when a page will not load, and the per-site controls for JavaScript, ad blocking, cookie notices, and storage.

Open Settings → Appearance → Language & emoji → Interface language. Choose with Left/Right, press X to install, then restart Tilefinch to apply. English is built in; downloadable translations are available for Spanish, French, German, Japanese, Russian, Ukrainian, Simplified Chinese, Korean, Hindi and Arabic. Choosing a language also downloads its required glyph pack if it is not already installed. Advanced messages not yet translated remain in English, and English stays available if a download fails.

This changes Tilefinch's menus—not the text of websites, games, or subtitles. Preferred video, audio and subtitle languages are separate settings.

The built-in fonts cover Latin text, with compact fallbacks for some Chinese, Japanese, Korean and emoji characters. Settings → Appearance → Language & emoji offers additional page-text packs: Japanese, Simplified Chinese, Traditional Chinese, Korean, Cyrillic (including Russian and Ukrainian), Extended Latin, Arabic, Hebrew and Devanagari (Hindi), plus a color emoji pack. A page using a missing pack can also offer to install it while you browse.

Confirm the corresponding pack download and restart to use it. Square removes an installed pack. Packs add glyph coverage; they do not translate page text. Arabic and Hebrew have right-to-left layout support. Hindi covers common syllables and interface clusters; unusual conjuncts may still use fallback cells.

Translations and signed packs are hosted in tilefinch-models, which lists the available downloads. Tilefinch verifies them before installation and keeps installed downloads on the Memory Stick for offline use. See the language-pack guide for installation, removal and missing-text notices.

Check for updates from Settings → Updates. An optional background check looks for new release information at most once a week and can be turned off; Tilefinch never downloads or installs an update unless you ask.

• Stable and Beta releases are cryptographically signed and verified before installation. The Developer channel, which you must select explicitly, is unsigned and trusts the endpoint you configure.
• A new version installs into a second slot and boots as a trial. If it fails to start properly, the launcher returns to the version that worked, and holding L at boot always starts the previous version.
• On Stable, press Square on the update page to choose an older signed release. It installs into the inactive slot and must pass the same trial boot.

docs/SECURE_UPDATES.md and SECURITY.md have the details.

• No telemetry, analytics, or accounts. Tilefinch sends nothing about you or your browsing anywhere. Requests to YouTube carry the configured video language (the PSP's language by default) so results and audio tracks can be localized.
• Everything the browser keeps stays on the PSP. Cookies live only in memory and are gone at power-off; history (off by default), the cache, saved pages and videos, screenshots, and settings are on your Memory Stick. Settings → Device & storage → Site data & storage lists the sites holding data and clears one of them, or HTTP caches, cookies, local storage, and session storage for every site.
• Site storage (localStorage, sessionStorage, and the origin-private file system) lives in RAM and is not written to the Memory Stick unless you choose. When a site outgrows RAM, Tilefinch asks before keeping that site's data on the Memory Stick, for this session or always, and shows how much it needs. Permissions & controls → Site storage sets the choice per site, and Site data & storage sets it for any listed site.
• To reconnect faster, Tilefinch normally keeps the short-lived TLS resumption tickets that servers issue, in data/tls-sessions.bin. They act as credentials, so they stay on your Memory Stick, are sent only back to the site that issued them, and are erased by Site data & storage → Clear HTTP caches. Settings → Privacy & security → TLS ticket saving stops keeping them between boots without disabling connection reuse within a session.
• The background update check contacts the GitHub releases API at most once a week if enabled. It compares version numbers, sends nothing identifying beyond an ordinary HTTPS request, and can be turned off. Downloads you request—including updates, language packs and interface translations—also contact their published download hosts.
• Help & diagnostics → Check Wi-Fi sign-in makes one cookie-free HTTP request to connectivitycheck.gstatic.com, only when you ask for it or accept a sign-in suggestion. A detected sign-in page opens with temporary cookies and storage that are deleted when it closes.
• On the start page, resting on the built-in YouTube tile for about a third of a second opens a connection to YouTube in the background, so the site is ready when you press X. This happens only for that built-in tile, never for a bookmark or an address a page supplied. It sends one bodyless request with no cookies, credentials, or referrer and fetches no content until you open the site. At most one such connection exists, and it closes as soon as you move away or the PSP suspends.
• Voice search runs entirely on the PSP; audio never leaves it.

The security model documents Tilefinch's security defaults, compatibility controls, threat model, and known isolation limits.

• Many sites render imperfectly and some heavy sites do not load at all; Tilefinch does not yet implement every web standard or API. A page that exceeds the memory budget degrades or stops loading instead of crashing.
• Heavy JavaScript applications are slow on a 333 MHz CPU. On a PSP-3000, chatgpt.com takes about 40 seconds before you can type, and a short reply takes about as long again after you send (measured from a recorded session; live network time adds to both).
• YouTube support depends on YouTube not changing; it breaks occasionally and updates fix it. Tilefinch does not generate YouTube Proof-of-Origin (PO) tokens, so videos that require one may stay unavailable even when browsing and search work.
• Voice search is experimental: slow, often wrong, and English only.
• Tabs keep a bounded record of each page's history, URL, focus, and scroll position rather than five complete pages, so switching tabs reloads the page through the shared cache. The switcher keeps one 60×34 preview per tab (about 20 KiB in total), taken from a frame that was already rendered. Optional Hibernate tab, off by default, moves one inactive tab's snapshot (not its page memory) to the Memory Stick and marks it [Z].
• Sites behind Cloudflare managed challenges do not work.
• WebGL is a bounded subset of the PSP's GE for conventional vertex-color and textured shaders, not a complete programmable GPU. Complex shaders, transparent drawing buffers, offscreen framebuffers, and large scenes fail softly instead of consuming unbounded memory or frame time.
• There is no desktop-grade process sandbox and no complete CSP. Tilefinch enforces a bounded subset of response-header CSP, resource, and framing policy, Subresource Integrity for scripts and stylesheets, and restrictive iframe sandbox and origin boundaries (see the security model), but it does not isolate origins in separate processes. Do not use it for sensitive accounts or transactions.

If something misbehaves, start with TROUBLESHOOTING.md. A useful bug report includes:

• the PSP model and custom firmware (for example "PSP-3000, ARK-4");
• the Tilefinch version from Help & diagnostics → Version & system;
• the site or URL, and what you pressed;
• after a crash, PSP/GAME/TILEFINCH/data/tilefinch-crash.txt from the Memory Stick (a 512-byte file of zeros means no crash was recorded).

Without easy Memory Stick access, Help & diagnostics → Diagnostic QR shows the same bounded logs as QR pages you can photograph. For suspected security problems, SECURITY.md explains what the project protects and how to report.

The desktop lab builds and tests the same engine on your computer, at PSP screen sizes and memory profiles. The first configure downloads hash-pinned dependencies; host builds need libcurl development headers and zlib.

cmake --preset release
cmake --build build-preset-release
ctest --test-dir build-preset-release

docs/DEVELOPMENT.md has the full workflow; read CONTRIBUTING.md before sending changes.

One engine runs everywhere. Parsing, styling, layout, scripting, and tile-based rendering are bounded and charged to a memory budget, and are designed so that a refused allocation, a malformed page, or a cancellation is a normal event rather than a crash. docs/ARCHITECTURE.md has the system diagrams, memory contracts, and lifecycle boundaries, and docs/README.md maps all of the documentation, including the engineering manuals in docs/engineering/.

Evaluating the engineering? Read in this order:

1. ARCHITECTURE: the system and its ownership rules.
2. SECURITY_MODEL: what fails closed, and which guarantees are absent.
3. The two device lifecycle contracts, for media and networking.
4. The device qualification strategy: which claims the host, the emulator, and the hardware can each prove.
5. RELEASE_PROCESS: gates, ratchets, and the offline signing ceremony.

Issues and pull requests are welcome. Tilefinch is a spare-time project, so responses and reviews may take a while. CONTRIBUTING.md describes the build and test expectations.

Tilefinch is MIT licensed; see LICENSE. Third-party components keep their own licenses and notices, listed in THIRD_PARTY_NOTICES.md. The security policy and vulnerability reporting are in SECURITY.md.

The browser download contains no acoustic model or speech dictionary. If you request the optional voice component in the app, its signed package carries the Alpha Cephei and CMUdict license files alongside the model; the browser bundle itself carries the PocketSphinx license that its linked decoder requires.

The optional Japanese, Chinese, Korean, Cyrillic, Extended Latin, Arabic, Hebrew, Devanagari (Hindi), and color-emoji packs are likewise not part of the download. They are generated from Noto fonts, carry the complete SIL Open Font License notice and a digest of the source font, and are fetched only when you ask for one. Tilefinch does not read the PSP's proprietary firmware fonts.

Tilefinch is an independent, unofficial homebrew project. It is not affiliated with, sponsored by, or endorsed by Sony Interactive Entertainment. PlayStation, PSP, and related marks belong to their respective owners. The project contains no proprietary Sony SDK material, firmware, artwork, or branding.

The Wikipedia screenshots show the English article "PlayStation Portable". Wikipedia text is licensed CC BY-SA 4.0. Wikipedia and its marks are trademarks of the Wikimedia Foundation, shown only to identify browser compatibility; Tilefinch is not affiliated with the Wikimedia Foundation.

The video screenshot shows a frame from Big Buck Bunny, copyright 2008 Blender Foundation, licensed CC BY 3.0. The film and its credits are available from the Blender open-movie project.