A replacement music player for the Sony NW-A55 Walkman and the rest of the NW-A50 series. It replaces Sony's music app with a faster one and keeps Sony's audio services, effects and DAC path underneath. Install it from a PC over USB; the same installer puts Sony's app back.

This is a personal project that I made for myself. If people want to tweak it and adapt it to their own use, please do, but I can't promise features or time for it. Raise issues in the issues section, but I can't promise they will be patched. Back up with wbrt before you install, and if you have the time and skill, please contribute pull requests. I have deliberately not included any way to sponsor or pay for this project. I want it to be free, and I don't want the obligation for support that comes with payment; as I said, I made this for me. The best way to support it is to test, give feedback and patch. Cinder is still in testing and development, whatever GitHub's labels say.

• Fast. About 4.6 MB of native code, no UI framework. Sony's app is Qt.
• A real queue. Up Next with play next, drag to reorder, and playlists made on the player.
• USB-DAC in, LDAC out, at once. Use the Walkman as a PC sound card and send the audio on to Bluetooth headphones. Sony's app blocks this; the hardware doesn't.
• All of Sony's sound features: DSEE HX, VPT, DC Phase Linearizer, Vinyl Processor, the 10-band EQ and tone control. Cinder drives Sony's own services rather than reimplementing them.
• Better battery. With the screen off, Cinder powers the display hardware down and lets the chip reach its deepest idle state. Sony's audio path is untouched.
• Extras: a .scrobbler.log scrobbler, lyrics (.lrc or embedded), library search, SensMe™ channels, FM radio with a signal meter, and colour palettes you drop on the drive.
• Your layout. Open on the Library, Now Playing, the Menu or wherever you left off. Optional pull-down panel for brightness, Bluetooth, night mode and the sleep timer.
• Your library as it is. Cinder reads Sony's database, so music, playlists and liked songs stay.

A daily player on the developer's own unit. Every CHANGELOG.md entry says whether it has run on hardware (device-verified). Per-feature state: cinder-home/STATUS.md.

Known issues

• v0.3.9 doesn't start after a fresh install (#16). Fixed in v0.3.12: install it over the top.
• Walkman One: the release package is rejected, silently. Walkman One changes the key the updater accepts. The installer warns when it sees Walkman One's CFW folder. Cinder itself runs on Walkman One 3.02, but a package sealed for it hasn't been tested yet. See Coming from Walkman One.
• Not built yet: Bluetooth receiver mode (Walkman as a speaker) and FM recording.
• One test unit. Other NW-A50-series models share its firmware but haven't been tried.

1. Back up the player with wbrt. There is no other recovery path for this device.
2. Download the installer from Releases:
   • Windows: cinder-installer-windows-x64.exe. Accept the administrator prompt; the last step needs raw drive access.
   • Linux: cinder-installer-linux-x64, run with sudo.
   • macOS can stage the files but can't send the final command. Use Windows or Linux.
3. Connect the Walkman in USB mass-storage mode, run the installer, choose Install and your options. The player reboots into its updater, installs, and starts Cinder. Leave the cable in until it does.

The installer also has Update (keeps your choices) and Uninstall (restores Sony's app; music and settings are untouched). It reads the player's logs, so it reports what is really installed. The .exe is unsigned; check it against SHA256SUMS on the release.

Every option, and the developer build: install.md. Removing it: UNINSTALL.md.

Each way back to Sony's player depends on less than the one before:

• Boot with the USB cable connected → Sony's player. Needs no filesystem. (The first boot after an install ignores the cable once.)
• A file named cinderhome_off on the drive → Sony's player until you delete it. cinderhome_clear clears a latched failure and tries Cinder again.
• A build that fails to start reverts to Sony's player by itself after four boots.

Read RECOVERY.md before you need it. Attach cinderhome.log (root of the drive) to any issue.

• Sound: Walkman One's plus modes are a 3-byte change to Sony's audio library. Cinder's signature install option makes the same change to your own stock files, no flashing. Its external tunings are other models' firmware and can't be reproduced. Measured at the jack, neither changes the signal (unknown321's measurements).
• Volume curve: Cinder removes Sony's regional volume limit by default; the region install option keeps it. The NW-WM1A curve is an install option if you supply Sony's table file (how).
• Installing over Walkman One: not with a release package yet. To help, run nvpstr kas on your player and post the output in an issue.
• Reverting to stock first works; Cinder installs on stock 1.02. If it then doesn't start, you're on v0.3.9 (#16): use a newer release.

Teardown of Walkman One: analysis/RE_walkmanone_extract.md.

Issues and pull requests are welcome. The most useful contribution is a device report: run one item from docs/DEVICE_CHECKLIST.md and post the result, pass or fail. CONTRIBUTING.md covers the local checks, the rules for boot-path code, and releases. Docs index: docs/README.md.

UI work needs no device: cd player && cargo run --release -p cinder-host renders every screen to player/out/. The device build needs a matched cross toolchain; see install.md and CLAUDE.md Parts A–D.

All 38 screens, from Now Playing to the Windows installer: docs/SCREENSHOTS.md.

Cinder's code is MIT (LICENSE). Bundled fonts are SIL OFL 1.1 (*-OFL.txt beside each). The repository contains no Sony code or artwork; the reverse-engineering notes describe interfaces only. Rockbox's nwztools (GPL) is used as an external tool, not vendored.

Not affiliated with or endorsed by Sony. "Walkman" and "SensMe" are Sony's marks.

As a disclaimer, a large amount of the reverse engineering work, documentation, and Rust and C++ code was written by Claude. All work was supervised and checked by a human.