build tooling

This repo contains a nix flake which implements tooling for easy development, fully reproduicable builds and without fear of a DMCA :3

The overlays directory only contains actual changes instead of the entire firmware source code. A local copy of the Firmware for development can be generated using nix run .#unpack where one then can make changes. After meowking the desired changes one simply runs nix run .#create-overlay to generate the patch files. This basically compares the local working copy against a imutable copy of the original firmware.

To build a ready-to-deploy fw image based of these patches one simply runs these 3 commands:

1. nix run .#unpack
2. nix run .#apply-overlay
3. nix run .#repack

Goals for Meowby:

My ultimate goal with this for is the implementation ofd a Open-Subsonic client for streaming from selfhoseted music servers.

---

the following contents of the README were created by bidhata over on GitHub (big thanks for that <3). some of these are implemented in this repo, others arent

HiBy R1 / MiDi R1 Firmware Modifications

Firmware patches for the HiBy R1 and MiDi R1 portable music players.
Device runs HiBy Linux on an Ingenic X1600 MIPS SoC with a Cirrus Logic CS43131 DAC/amp chip.

---

Changes Made

1. Volume Cap Removed

File: usr/resource/config.json

The player hard-capped the UI volume slider at 50/100 steps regardless of the CS43131's actual output range.

Field	Before	After
lock_vol[headset]	50	100
warn_vol[headset]	34	100

---

2. MDB / LDB Hardware Gain Tables Fixed

File: usr/resource/ot_devices.json

The MDB and LDB volume tables stopped at CS43131 register value 12 instead of 0.
Register 0 = 0 dB (true maximum output). Register 12 ≈ −0.75 dB below full output.
Changed the last entry in both MDB and LDB Values arrays from 12 → 0.

---

3. Native DSD Enabled

File: usr/resource/ot_devices.json

All three DSD output paths were forced to DoP even when the user selected Native mode.
The CS43131 supports hardware native DSD over I2S.

Field	Before	After
AnalogDsdNative	"dop"	"native"

AnalogDsdD2p and AnalogDsdDop remain as "dop" — correct for their respective modes.

---

4. Missing Audio Engine Keys — Investigated, Not Applied

File: usr/resource/ot_devices.json

Reverted — not applied in this build.

The player binary reads several keys from ot_devices.json that were absent in stock firmware, causing fallback to hardcoded defaults. The following keys were tested:

"DOP_MAX_VOLUME":           100,
"ANALOG_PCM_HW_SAMPLE_MAX": 384000,
"SPDIF_MAX_VOLUME":         100,
"USB_OUT_MAX_VOLUME":       100,
"USE_VOLUME_CHIP":          0,
"SW_MIX_GAIN_ENABLE":       1,
"SPDIF_MAX_192K":           0

ANALOG_PCM_HW_SAMPLE_MAX: 384000 matches the CS43131's hardware ceiling and the analog device SampleRate list already declared in the same file.
SPDIF_MAX_192K: 0 removes the 192 kHz cap on the SPDIF output path.
USE_VOLUME_CHIP: 0 — must be 0 if used. Setting this to 1 forces volume writes directly to the CS43131 ALSA hardware registers, which are not wired up in this firmware version. With 1, the volume buttons show UI movement but produce no audio change.

These keys were removed after testing — the firmware behaves correctly without them using its built-in defaults.

---

5. Hardware-Only Volume Control

File: usr/resource/ot_devices.json

⚠ Reverted — do not set to 0.
Setting SET_HW_SW_VOL_BOTH: 0 causes the volume buttons to show UI movement with no audio change (volume buttons stop working). Leave at 1.

Field	Value
SET_HW_SW_VOL_BOTH	1 (stock value — leave unchanged)

SET_HW_SW_VOL_BOTH: 1 means the firmware applies volume changes to both the CS43131 hardware registers and the software attenuation stage simultaneously. Setting it to 0 was expected to use HW-only volume, but on this firmware version the result is that neither path is driven — the UI slider moves but audio level does not change. This change has been reverted.

---

6. Internet Radio Enabled for English — MiDi R1

File: usr/resource/layout/midi/theme1/hiby_stream_media.view

On the MiDi R1 the Stream Media screen only showed Tidal and Qobuz for non-Chinese languages. The radio entry was present in hiby_stream_media_cn.view but absent from the base layout file loaded for all other locales.

Added the stream_media_vg_radio viewgroup block (identical to the CN variant) between the closing of stream_media_vg_qobuz and "name":"vg_stream_media_hiby".

---

7. Internet Radio Enabled for English — HiBy R1 Theme 1 & Theme 2

Files:

• usr/resource/layout/theme1/hiby_stream_media.view
• usr/resource/layout/theme2/hiby_stream_media.view

Same fix applied to the standard HiBy R1 themes to ensure radio is visible under all language settings.

---

8. Bluetooth Audio Quality — SBC XQ

File: usr/bin/bt_init

Added --sbc-quality=xq to the BlueALSA launch. SBC XQ uses bitpool 76 in dual-channel HD mode (~500 kbps). Falls back automatically to standard high quality (bitpool 53) if the connected device does not advertise XQ support.

BlueALSA launch line:

/usr/bin/bluealsa -p a2dp-source --a2dp-volume --sbc-quality=xq &

---

9. Font Replaced — Roboto

File: usr/resource/fonts/default.otf

Removed the stock default.otf (155 KB, HiBy custom font) and replaced it with the Roboto font family as default.otf (~10 MB total). Roboto provides broader Latin/Cyrillic coverage and better legibility at small display sizes.

Also removed Thai and Korean locale string directories — these are no longer needed since Roboto does not carry Thai or Korean glyph ranges:

Removed	Path
Thai locale strings	usr/resource/str/thai/
Korean locale strings	usr/resource/str/korean/

Note: Place your Roboto .otf file at usr/resource/fonts/default.otf before repacking the firmware image. The hiby_player binary loads the font by this exact filename.

---

10. Patched hiby_player Binary — Sorting Fix

File: usr/bin/hiby_player

Replaced the stock player binary with the community-patched sorting variant from hiby-modding/hiby-mods.

What the sorting patch changes:

Behaviour	Stock	Patched
Article handling	"The Beatles" sorts under T	Strips leading articles (the, a, an, and equivalents in 13 languages) before sorting
Symbol-prefixed titles	Mixed into alphabet	Sorted first (before A)
Multi-language sort	ASCII only	Unicode-aware; handles CJK, Cyrillic, Latin extended, etc.

Source: https://github.com/hiby-modding/hiby-mods/tree/main/binaries
Compatibility note: The upstream repo primarily targets the HiBy R3 Pro II. Tested to boot and function on the R1 — verify your own build before flashing.

---

Summary Table

#	Change	File
1	Volume cap lifted 50 → 100	usr/resource/config.json
2	MDB/LDB gain table ceiling 12 → 0 (true 0 dB)	usr/resource/ot_devices.json
3	Native DSD output enabled (AnalogDsdNative)	usr/resource/ot_devices.json
4	Audio engine keys added REVERTED — defaults are sufficient	usr/resource/ot_devices.json
5	HW-only volume (SET_HW_SW_VOL_BOTH 1 → 0) REVERTED — breaks volume buttons	usr/resource/ot_devices.json
6	Internet Radio enabled for English — MiDi R1	usr/resource/layout/midi/theme1/hiby_stream_media.view
7	Internet Radio enabled for English — HiBy R1 (Theme 1 & 2)	usr/resource/layout/theme1/hiby_stream_media.view, theme2/...
8	SBC XQ enabled (~500 kbps, bitpool 76)	usr/bin/bt_init
9	Font replaced: stock default.otf → Roboto (~10 MB); Thai & Korean locale strings removed	usr/resource/fonts/default.otf
10	Patched player binary — article/symbol sort fix	usr/bin/hiby_player

---

Hardware Reference

Component	Details
SoC	Ingenic X1600 (MIPS32r2)
DAC / Amp	Cirrus Logic CS43131 (I2C bus 3, GPIO PB02 power, PB21 reset)
PMU	X-Powers AXP2101
OS	HiBy Linux (kernel 4.4.94)
Display	LG35583 480×800
WiFi	Cypress CYW (cywdhd)
Headset ADC	sa_earpods_adc on AXP2101 ALDO4

---

CS43131 Capabilities (Unlocked by These Changes)

Feature	Spec
PCM	32-bit, up to 384 kHz
DSD	DSD64 / DSD128, Native or DoP
SNR	130 dB
THD+N	−107 dB
Output power	~112 mW @ 16 Ω
Digital filters	5 hardware modes (fast/slow rolloff × min-phase/linear-phase + apodizing)

---

Sound Tuning — MSEB

HiBy's MSEB (Multi-dimensional Sound Enhancement Bass) is the primary tool for shaping the sound signature on-device.

Path: Play Settings → MSEB

Slider	Range	Bass-relevant direction
Bass extension	Light ↔ Deep	Deep = more sub-bass
Bass texture	Fast ↔ Thumpy	Thumpy = more decay/weight
Note thickness	Crisp ↔ Thick	Thick = more body
Overall Temperature	Cool/Bright ↔ Warm/Dark	Warm = darker, fuller tone

Tap the settings icon inside MSEB to set the adjustment range: Fine-tuning (±20), Middling (±40), or Excessive (±100). Set to Middling or Excessive before pushing sliders far.

---

Digital Filters

CS43131 Chip Filters (in-app, Play Settings → Digital Filter)

These are the CS43131's hardware oversampling filter modes, confirmed from the codec_cs43131.ko ALSA driver. They are exposed as an ALSA control named Digital Filter and accessible in-app via Play Settings → Digital Filter. They affect HF rolloff shape and transient pre/post-ringing — not bass level.

ALSA value	In-app label	Rolloff	Phase	Character
0 (fast_rolloff_low_latency)	Minimum-phase	Fast	Minimum phase	No pre-ringing, some post-ringing
1 (fast_rolloff_phase_compensated)	Sharp / late rolloff	Fast	Linear phase	Symmetric pre+post ringing
2 (slow_rolloff_low_latency)	(not in UI)	Slow	Minimum phase	Gentle rolloff, no pre-ringing
3 (slow_rolloff_phase_compensated)	Slow / early rolloff	Slow	Linear phase	Gentlest rolloff, symmetric ringing
4	(not in UI)	Fast	Apodizing	Minimised pre-ringing, near-linear phase

Values 2 and 4 are not exposed in the in-app Digital Filter dialog and are only accessible via ADB:

# slow rolloff, minimum phase
adb shell amixer cset name='Digital Filter' 2

# apodizing fast roll-off
adb shell amixer cset name='Digital Filter' 4

# read current value
adb shell amixer cget name='Digital Filter'

---

Hidden Features Found (Not Yet Enabled)

Feature	Location	Notes
Factory test mode	usr/resource/layout/theme1/test/hiby_test.view	LCD, touch, key, BT, WiFi, FM hardware tests. Strings only in simplified_chinese and english locales

---

Enabling ADB

ADB can be enabled on any firmware version (including stock) without any modification:

1. Go to Settings → About
2. Tap the "About" text 10 times
3. A "Developer Mode" confirmation message will appear
4. Connect the device to your PC via USB
5. Run adb devices to confirm the connection

To disable ADB, tap "About" 10 times again — the same toggle also disables developer mode.

Note: ADB and USB mass storage share the same USB interface and cannot run simultaneously. While ADB is enabled the device will not appear as a storage drive.

Note: This enables Developer Mode (ADB access), not the separate factory Test Mode. The factory test suite (hiby_test.view — LCD, key, touch, audio, BT, WiFi hardware tests) is a distinct feature with an unknown trigger, likely a button combination at boot. It is not accessible via the About tap sequence.

How It Works Internally

The tap-counting logic lives entirely inside the hiby_player binary. The About screen (hiby_about_dev.view) contains a hidden textview (about_dev_tv_developer) that the binary progressively reveals as you tap. The locale strings confirm the countdown behaviour:

String key	Text
enter_developer_mode	"Perform 2 more steps to enter development mode"
developer_mode	"You are already in developer mode"
in_developer_mode	"You are already in developer mode, no need to do this."

The ADB toggle is a flag file: /usr/data/disableadb

• File present → ADB is blocked. Both init scripts (S310adb, S440adb) check for this file at startup and exit early if it exists.
• File absent → ADB starts normally.

When you tap 10 times, hiby_player creates or removes this file and immediately starts or stops adbd — no reboot required.

USB gadget configuration (from etc/init.d/adb/):

Field	Value
Vendor ID	0x18d1 (Google)
Product ID	0xd002
Device serial	{prefix}_{last 4 digits of WiFi MAC}, falls back to chip ID

Using Google's standard ADB VID/PID means no custom driver is needed on the host PC — the device shows up immediately with a standard ADB installation.

---

Battery Optimizations

1. batd Battery Logger Disabled

File: usr/bin/hiby_player.sh

batd is a debug battery-monitoring daemon. When its binary is present it was launched at every player start with -t5, writing a battery log to the SD card every 5 seconds. This causes the SD card to wake on a 5-second cycle even during playback from internal storage.

The launch block has been removed. The batd binary itself is untouched — reinstating logging is a one-line change if needed.

Field	Before	After
SD card wakeup interval	Every 5 s (continuous)	Never

---

2. Red LED Breathing Animation Disabled

File: module_driver/leds_pwm_add.sh

The red LED was set to breathing trigger — a continuous PWM fade-in/fade-out effect active whenever the device was on. Changed to none (LED off).

Field	Before	After
led_pwm0_trigger	breathing	none

To restore the breathing effect or use a different trigger (heartbeat, default-on, etc.) edit this file.

---

3. Bluetooth Discoverable / Pairable Timeouts

File: etc/bluetooth/main.conf

Both timeouts were 0 — meaning the device stayed permanently discoverable and pairable after BT was enabled, continuously advertising over the air. Set to 180 seconds (BlueZ default).

Field	Before	After
DiscoverableTimeout	0 (forever)	180 s
PairableTimeout	0 (forever)	180 s

After 3 minutes with no pairing the device stops advertising. Already-paired devices reconnect normally — this only affects new-pairing discovery broadcasts.

---

HiBy R1 — File Limit Patch (50,000 → 65,000 Tracks)

Target binary: /usr/bin/hiby_player (MIPS32 LE ELF, 4,855,400 bytes)
Change: Increases the music database track limit from 50,000 to 65,000 (0xC350 → 0xFDE8)

---

Patch Locations

Offset (hex)	Offset (dec)	Before	After	Instruction
0x000EDF74	974,708	50 C3 02 34	E8 FD 02 34	ORI $v0, $zero, 65000
0x002DE3B0	3,007,408	50 C3 02 34	E8 FD 02 34	ORI $v0, $zero, 65000
0x002DFEA0	3,014,304	50 C3 04 34	E8 FD 04 34	ORI $a0, $zero, 65000
0x002E937C	3,052,412	50 C3 04 34	E8 FD 04 34	ORI $a0, $zero, 65000

---

How to Apply

Back up your original binary before patching.

Using dd on Linux/macOS:

FILE="hiby_player"
cp "$FILE" "${FILE}.orig"
for offset in 974708 3007408 3014304 3052412; do
    printf '\xe8\xfd' | dd of="$FILE" bs=1 seek=$offset conv=notrunc
done
----

# HiBy R1 Sound Enhancement

Config-only audio improvements for the HiBy R1 portable DAP. No binaries compiled. All changes are reversible.

---

## What This Does

| Change | File | Effect |
|--------|------|--------|
| ALSA PCM pipeline | `usr/data/asound.conf` | High-quality resampling + 256-step software volume |
| Volume tuning | `usr/resource/config.json` | Lower startup volume, wider range |
| EQ preset rename | `usr/resource/str/english/eq.ini` | "Custom" → "Headphones" slot for PEQ settings |

---

## Device

- **Model:** HiBy R1
- **OS:** Embedded Linux (MIPS32, kernel 2.6.32)
- **DAC:** Cirrus Logic CS43131 — confirmed at card 0 (`pcmC0D0p`)

---

## Files Changed

usr/data/asound.conf ← ALSA plug + softvol chain usr/resource/config.json ← Volume defaults usr/resource/str/english/eq.ini ← EQ preset label

**Originals backed up in:** `docs/superpowers/backups/`

---

## ALSA Signal Chain

hiby_player └── pcm.!default (asym) └── playback → pcm.sv_out (softvol, 256 steps, −51 dB to 0 dB) └── pcm.hq_out (plug, resampling) └── hw:0,0 (CS43131 DAC) └── capture → hw:0,0 (direct)

---

## Volume Settings

| Setting | Before | After |
|---------|--------|-------|
| Default volume | 20 | 15 |
| Warning threshold | 34 | 42 |
| Max (lock) volume | 50 | 60 |

---

## Deploy

### Option A — ADB push (device running)

```bash
adb push usr/data/asound.conf /usr/data/asound.conf
adb push usr/resource/config.json /usr/resource/config.json
adb push "usr/resource/str/english/eq.ini" "/usr/resource/str/english/eq.ini"
adb shell reboot

Option B — Repack squashfs

mksquashfs squashfs-root hiby_r1_enhanced.sqsh -comp xz -b 131072 -no-xattrs

Flash via OTA or recovery mode.

---

After Flashing — Manual Setup

Configure once on the device:

1. ReplayGain — Settings → Play → ReplayGain → select by Track
2. Crossfade — Settings → Play → Crossfade → On
3. Gapless playback — Settings → Play → Gapless playback → On
4. Parametric EQ — Settings → Equalizer → select Headphones → tap PEQ

PEQ settings (Headphones preset):

Band	Type	Frequency	Gain	Q
1	Low Shelf	100 Hz	+3.0 dB	—
2	Peaking	3000 Hz	+1.5 dB	1.2
3	High Shelf	10000 Hz	−2.0 dB	—

---

Disclaimer

These are filesystem-level config and layout file edits — no kernel modifications.
Changes affect audio output levels. Use appropriate volume and hearing protection.
Flash and use at your own risk.