EchoPod

Replacement firmware for the Snowsky (FiiO) Echo Mini 8 GB music player. It has an iPod-style Cover Flow browser, a music library built on the player, album favorites, M3U playlists and an Up Next queue. It isn't made or supported by FiiO.

• Installing and using it: docs/user-guide.md.
• Read first: docs/known-issues.md. EchoPod is early, and has been tested on one player.
• What's new: docs/release-notes.md.

The hardware knowledge it relies on comes largely from the ReChord project's research (docs/hardware.md, CREDITS.md).

What it does

• Plays FLAC, ALAC, MP3, AAC, Opus and WAV, from 44.1 to 192 kHz with 24-bit output, gapless.
• Cover Flow, with every album and a Random album tile, and Now Playing with the cover, progress and seeking.
• A library built on the player: Artists, Album Artists, Albums, Genres, Folders, All Songs, Playlists (M3U and M3U8) and Favorites, with fast scroll and letter jumps. Or build it on a computer with echo-sync.
• Queue and modes: shuffle songs or albums, repeat, and Up Next (Play Next, Add to Up Next). The queue and position come back after power-off.
• Equalizer: FiiO's presets and a 7-band Custom EQ.
• Portrait mode: Settings → Orientation turns the screen upright either way, with layouts made for it. The volume rocker turns with it.
• Languages: Settings → Language: English, Simplified Chinese, Japanese, Korean, German, French, Spanish, Italian, Portuguese, Dutch, Swedish, Danish, Norwegian and Finnish. The choice applies after a restart. Titles and artists in Cyrillic, Greek, Polish, Czech, Turkish, Romanian and Vietnamese letters draw too.
• Audiobooks and podcasts on their own shelves, with a bookmark for each.
• Bluetooth headphones: pairing, up to six remembered, reconnecting by itself.
• USB: both drives as mass storage, or the player as a USB DAC.
• Everyday controls: pause, volume and skip with the screen off, a sleep timer, auto off and a charge screen.
• Chinese, Japanese and Korean names.
• Updates itself from a file copy, and goes back to FiiO's firmware the same way.

Build and run the simulator (macOS)

brew install cmake sdl2 clang-format arm-none-eabi-gcc arm-none-eabi-binutils
python3 -m venv .venv && .venv/bin/pip install -r tools/requirements.txt
cmake --preset dev
cmake --build --preset dev
ctest --preset dev
./build/dev/platform/sim/echo_sim

Build on Windows

Install MSYS2 and, in its CLANG64 shell, the packages mingw-w64-clang-x86_64-{clang,compiler-rt,cmake,ninja,SDL2} and mingw-w64-clang-x86_64-arm-none-eabi-{gcc,binutils,newlib}, plus Python 3 with pip install -r tools/requirements.txt. With C:\msys64\clang64\bin first on the PATH (and not C:\msys64\usr\bin, whose git ignores this repo's line endings):

CMAKE_GENERATOR=Ninja CC=clang cmake --preset dev
cmake --build --preset dev
ctest --preset dev

Build the firmware

cmake --preset release
cmake --build --preset release

This writes build/release/HIFIEC90.IMG. The device preset builds the same image with the developer Diagnostics rows. docs/device-install.md covers installing builds during development.

Use your music library in the simulator

mkdir -p build/system
./build/dev/platform/sim/echo_sim --card /path/to/music --system-dir build/system

The simulator behaves like the player: on the first start it creates library.db, covers.bin and the save files in the system folder, scans the music folder (every format stock lists, plus .m3u/.m3u8 playlists) and finds the album covers. Settings → Rescan library scans again. The music folder is only ever read.

The PC tools still work and write the same formats (tools/library_index.py, tools/cover_export.py), but the player doesn't need them. To skip the scan on the player, echo-sync builds the library, the covers and the music fingerprint (scan.bin) on a computer, straight into the card's /.echo folder, so the player's check after USB finds nothing to rescan (docs/user-guide.md, Build the library on a computer). Each release carries it as one file for Windows, macOS (Apple silicon) and Linux, with nothing to install, built by .github/workflows/echo-sync.yml with PyInstaller; from the source it's tools/echo_sync.py E:. To build the file yourself: python -m pip install -r tools/requirements.txt -r tools/requirements-build.txt, then python -m PyInstaller --onefile --name echo-sync --paths tools tools/echo_sync.py.

Testing on a player

1. Install the firmware (docs/user-guide.md, or docs/device-install.md for development builds).
2. Put music on a microSD card (FAT32 or exFAT), in any folder layout, and insert it.
3. Switch on. The player creates /.echo on the card, scans it ("Scanning library", then "Finding covers") and shows "Library: N tracks, M covers".
4. After copying music over USB, eject both drives: the player rescans by itself. Settings → Rescan library does it on demand.

Nothing else on the card needs a computer. Covers come from art embedded in each album's first track (FLAC, MP3/WAV/DSF/DFF ID3, MP4, APE, WMA) or a cover/folder/front/albumart JPEG or PNG next to the tracks.

Simulator keys

Device button	Keyboard
Volume up (moves menus down)	Down arrow
Volume down (moves menus up)	Up arrow
Play	Return or Space
Menu	M or Tab
Back	Backspace or Escape
Power	P

Simulator options

Option	Effect
--scale N	Window scale (default 3)
--frames N	Quit after N frames
--headless	No window
--screenshot FILE.bmp	Save the last frame on exit
--card DIR	Use DIR as the card root (read only)
--system-dir DIR	Read and write /.echo/ (library database, resume, settings, favorites) in DIR
--battery N	Report N % battery in the header (default 80)
--charging	Report the battery as charging
--keys LIST	Play a key script, e.g. down,down,play,back:long (up, down, play, menu, back, power, each optionally :long)

Headless runs use a virtual clock, so scripted screenshots are deterministic.

Navigation

Button	In lists	On Now Playing	While seeking
Volume up / down	Next / previous item (wraps on a single press, not while held)	Tap for volume; hold Vol+ for the next track, Vol− for the previous one	Forward / back 5 s per tap, 15 s steps while held
Play	Select (a song plays the list from that song); hold on an album to add or remove it from Favorites	Play / pause; hold to seek	Jump to the chosen time
Menu
Back	Back; hold to go home	Back; hold to go home	Cancel
Power	Screen off or on; hold 2 s to turn off	Same	Same

The screen turns off after the screen timeout or a tap of Power. With the screen off, Play pauses and resumes, a tap of vol± changes the volume and holding vol± skips tracks, all without waking the screen; Power turns it back on.

Home also lists Audiobooks and Podcasts when the card has an Audiobooks or Podcasts folder: every book and episode remembers where you stopped, plays in order, and hold vol± jumps 30 s forward or 15 s back. Books and episodes stay out of the Music lists (docs/user-guide.md).

Settings: Shuffle (Off / Songs / Albums), Repeat (Off / One / All), Sleep timer, Screen timeout, Brightness, Gain, Output and Start screen. They're saved in /.echo/settings.bin, and favorites in /.echo/favorites.bin. Without --system-dir the simulator can't save, and says so. Playback resumes, paused, where it left off.

Music → Cover Flow shows your albums as covers, by album artist. Vol± move, Play opens the album, holding Play adds or removes it from Favorites, and Back leaves. Music → Playlists lists the M3U playlists the indexer found. Music → Favorites lists your favorite albums.

Layout

See docs/architecture.md.

License

GPL-3.0-or-later. See LICENSE. The bundled Inter font is under the SIL Open Font License 1.1 (assets/fonts/inter/OFL.txt), and so are the Chinese, Japanese and Korean glyph packs made from Noto Sans CJK SC (assets/fonts/noto-cjk/OFL.txt). The simulator's decoders (dr_flac, dr_mp3, dr_wav) are public domain or MIT-0 (third_party/dr_libs/LICENSE). The player's MP3 decoder is libmad, GPL-2.0-or-later (third_party/libmad/COPYING).