Ogg Opus for the SNOWSKY ECHO MINI

This project adds Ogg Opus (.opus) playback to the SNOWSKY ECHO MINI digital audio player, and improves the sound quality of Ogg Vorbis (.ogg) files. It patches the official V3.9.0 firmware (HIFIEC39.IMG, 8 GB model). To make room for Opus, WMA support is removed.

Status: validated on the device (October 2026).

⚠️ Disclaimer. This is unofficial firmware patch. Flashing it may brick the device. A community MaskROM recovery procedure exists (see Recovery) but was not tested by this project. Use at your own risk. This project is neither affiliated with nor endorsed by SNOWSKY. This is a one man project, mostly done with AI, tested on one device. You have been warned.

What changes compared with the stock firmware

• .opus files play, with seeking, tags (title, artist, album, genre, track number), cover art, and "OPUS" on the playback screen. An Opus file named .ogg also plays.
• .ogg Vorbis files sound better: the stock decoder works at reduced precision, and is replaced by a full-precision one (see below).
• WMA is no longer supported: .wma files no longer appear in the browser.
• MP3, FLAC and the other formats are unchanged.

Full-precision Ogg Vorbis

The stock Vorbis decoder is built in a low-accuracy mode: its output has roughly 7 effective bits, and the added noise may be audible in quiet passages and fade-outs. This project replaces it with the same decoder (Xiph's Tremor) at full accuracy, about as precise as a PC decoder, for slightly less processing than the stock one. Tags, cover art and seeking work as before.

HIFIEC58 also runs the audio core at the MP3 speed (300 MHz instead of 400–480 MHz) while playing Ogg Vorbis, since the new decoder needs far less. Whether this saves battery has not been measured.

Which image?

Image	Contents
HIFIEC58 (recommended)	Opus + full-precision Vorbis, Ogg played at the MP3 clock speed.
HIFIEC56	Opus + full-precision Vorbis, stock clock speed for Ogg.
HIFIEC52	Opus only (stock Vorbis decoder).
HIFIEC50	Opus only, built with an unmodified libopus (reference build).

Known limits

• 8 GB model only (HIFIECxx.IMG). The 512 MB model (MINIVxx.IMG) is not supported.
• The firmware looks for tags and cover art only at the very start of an Ogg file (about 4 KB). Long lyrics can push them out of reach. Workaround, without re-encoding: ffmpeg -i in.opus -c copy -metadata LYRICS= out.opus.
• The firmware never displays progressive JPEG cover art, whatever the audio format. For .ogg files, tools/cover_baseline.py DIR --apply re-encodes such covers as baseline JPEG (only the picture is rewritten; run it without --apply first, and keep a backup). Requires mutagen and Pillow.

Installation

See INSTALL.md. In short: get the official HIFIEC39.IMG, then:

python3 patch/apply_patch.py apply HIFIEC39.IMG patch/HIFIEC58.ecpatch HIFIEC58.IMG

Then copy HIFIEC58.IMG alone to the root of the internal storage and reboot. Ready-made patches are also attached to each release.

Recovery

If an update goes wrong but the player still boots, install the back-to-stock image (see INSTALL.md, section 4).

If the player no longer boots at all (black screen), the community documents a low-level recovery through the Rockchip MaskROM mode: the player is put into MaskROM with the reset button, then a stock firmware image is written over USB with rkdeveloptool. See livetrack.club/debrick. This procedure was not tested by this project; follow it at your own risk.

For developers

• docs/BUILDING.md: building the images from source (bit-identical to the patches), off-device validation, repository layout.
• docs/OPUS_PORTING.md and docs/TREMOR_PORTING.md: how the decoders were fitted into the firmware, optimised and validated, with checklists for other players.
• docs/REPORT.md: the reverse-engineering report.
• docs/IMAGE_HISTORY.md: history of the test images.

Acknowledgments

More ambitious custom firmware projects exist for this player, and are worth a look:

• RECHO by atzkey: a from-scratch firmware for the ECHO MINI (gapless playback, improved navigation, files in name order).
• ReChord: a from-source custom firmware for the ECHO MINI, in progress.

This project is independent from both and shares no code with them (but I will be happy to share).

License

• This project's code: BSD-3-Clause (LICENSE).
• libopus and Tremor: BSD-3-Clause, see THIRD_PARTY.md and LICENSES/. The patches to them are distributed under the same license.
• The SNOWSKY firmware is not distributed.