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Quick Links

• Firmware Repository: CloudZao/MetalioClaw4
• Upstream Architecture: XiaoZhi AI (xiaozhi-esp32)
• ESP-IDF Official Documentation: ESP32-P4 Getting Started v5.5.4

1. Product Overview
2. Key Feature
3. Application Scenarios
4. System Architecture
5. Hardware Specifications
6. Dual‑Chip Architecture
7. Peripherals and Pins
8. Schematic Explanation
9. Software Architecture
10. Built-in OpenClaw
11. Built‑in Applications
12. Communication Protocols
13. Development Environment
14. Compilation and Flashing
15. Debugging and Common Issues

Recent additions: runtime UI i18n, standby screen, Settings / Test, ESPClaw dual-boot, SD virtual USB drive, chat emotion mode, internet radio, recording (Opus + ASR transcription), and related sections below.

Metalio Claw4 is an open‑source portable AI‑enabled device aimed at developers and makers. The whole unit is about 8×8 cm (palm‑size) and integrates a 3.95‑inch 720×720 touchscreen, microphone array, speaker, camera, GPS, wireless charging, and dual‑mode networking, allowing offline wake‑up followed by voice interaction with cloud AI.

• Offline Wake‑up: ESP‑SR based wake‑word detection
• Streaming ASR / LLM / TTS: Real‑time speech recognition, large‑model inference, and speech synthesis
• Device‑side AEC: Echo cancellation for full‑duplex conversation
• Dual‑Protocol Cloud Link: WebSocket or MQTT+UDP, flexible backend integration

OpenClaw is the cloud AI Agent platform running on Metalio Claw4. Users interact with the cloud Agent via natural language through the OpenClaw App on the home screen.

• Voice Conversation: Hold‑to‑talk to send commands and engage in multi‑turn dialogue with the cloud Agent
• Session Management: Supports viewing and clearing conversation history

API details and device‑side capabilities are described in §10 OpenClaw.

• Photo Preview: OV2710 MIPI‑CSI camera, 2 MP (1920×1080), real‑time preview and capture in the Camera app
• Outdoor Positioning & Navigation: The Location app provides GPS, Wi‑Fi, and base‑station tabs; the latter two are obtained via the 4G module, suitable for environments without GPS signal or indoors
• Magnetic Field Observation: The Magnet app shows real‑time three‑axis magnetometer data for field visualization and simple detection
• Level Measurement: The Spirit Level app uses the accelerometer to detect tilt angle, aiding placement and calibration

• Wi‑Fi: ESP32‑C5 coprocessor connected via SDIO, supporting 2.4 GHz and 5 GHz dual‑band Wi‑Fi
• 4G LTE: NT26 cellular module, factory‑installed 4G SIM‑patch; supports internal card / external card dual‑slot (see below)
• Bluetooth Audio: Professional Bluetooth audio codec hardware handling voice codec, Bluetooth speaker, and Bluetooth headset connections (see §12.1)
• Virtual USB drive: From the SD Card app, expose microSD as USB MSC to a PC (shares GPIO24/25 with USB Serial/JTAG — mutually exclusive; see §14.6)

Metalio Claw4 ships with an embedded 4G SIM‑patch (internal SIM). The NT26 module also provides an external SIM slot; users may install their own SIM card. In 4G network mode, the Network Configuration app’s SIM Switch page lets you toggle between internal and external cards; the status bar shows whether the current SIM is “Internal Card” or “External Card” .

• Phone Calls: Only the external SIM can dial via the Phone app; using the internal SIM prompts a switch to external SIM
• 4G Data: Both internal and external SIMs can be used for cellular data (after switching to 4G mode in Network Configuration)

Besides GPS satellite positioning, the NT26 module supports cellular‑network assisted positioning. In the Location app this appears as independent tabs:

Wi‑Fi / base‑station positioning needs the device to be in 4G network mode with the module successfully registered; results can be viewed as coordinates and opened as a static map inside the app.

Metalio Claw4 replaces the ES8311 + ES7210 discrete solution with a professional Bluetooth audio codec that covers three use cases with a single hardware set: (1) daily XiaoZhi voice interaction (mode 1), (2) connecting Bluetooth headset/speaker for XiaoZhi dialogue (mode 2), (3) phone‑to‑device Bluetooth speaker playback (mode 3). Mode switching, operation steps, and AT commands are detailed in §12.1.

• Single‑cell Li‑ion + TI BQ27220 fuel gauge (I2C 0x55)
• Wireless Charging: NU1680 receiver chip (I2C 0x60), supports Qi wireless charging; charging current configurable via register NU1680 charging current control
• USB Charging Detection: IO extender USB_INSERT_DET pin
• Low‑Voltage Protection: Device powers off automatically when booting at 0 % and not charging
• Standby & shutdown (configurable): While on the home screen, idle policy is controlled by Settings → Standby (idle_power_policy):
  • Enter standby: Default ~1 minute idle → standby_screen (large clock; charging shows blue particle effect ~10 s)
  • Cumulative shutdown: Default ~5 minutes idle (home + standby) → software power‑off; either slider set to 0 disables that action
  • Entering another app stops the idle timer; any touch resets it. Side‑key short‑press enters standby only when home is in foreground
• Power‑Management IC: Hardware long‑press ≈ 1 s to power on, ≈ 5 s to force‑off; firmware can trigger a software power‑off via a pulse on the IO extender (see Power‑IC & Power Key)

Power on/off is handled by a dedicated power management IC, independent of the main MCU. The physical power button connects both to the power IC and to the TCA9555 IO extender: MCU reads the button state via PWR_KEY and simulates a button pulse to the power IC via PWR_KEY_PULSE.

Firmware pins (see §7.3):

During firmware shutdown, pulses are sent to PWR_KEY_PULSE continuously: high 100 ms / low 100 ms in a loop, until the power IC cuts power (the task ends with the power loss). Used for UI “shutdown”, low‑voltage protection, and home‑screen idle auto‑power‑off. Logic resides in home_screen.cc (PwrShutdownPulseTask) and metalio-claw-4.cc (boot‑time low‑voltage protection).

When the device is already on, detecting a long press of PWR_KEY for ≈ 1.5 s triggers a “Restart / Shutdown” dialog; choosing shutdown follows the same continuous pulse. The dialog footer reminds: Long‑press power key 5 s for forced shutdown (hardware behavior).

NU1680 sets its over‑current protection limit via the low 3 bits [2:0] of I2C register 0x1E (MTP_ILIM_SET, R/W, reset default 0x00). When writing, only bits [2:0] are modified; the high 5 bits remain unchanged.

On detecting NU1680 online (I2C 0x60), firmware defaults to writing 0x00 to 0x1E (1.4 A) and writes 0x00 to 0x15 to disable temperature protection. See main/boards/metalio-claw-4/metalio-claw-4.cc.

Metalio Claw4 ships with 20+ built‑in apps. Developers can mix, trim, or secondary‑develop based on existing hardware/software to turn apps into vertical solutions. The table below lists example scenarios (not a fixed factory configuration).

flowchart TB
    ui["User Interaction Layer<br/>720x720 LVGL 9 Touch UI · Voice Wake-up · Power Key PWR_KEY"]
    apps["Application Layer<br/>Chat · Radio · Recording · OpenClaw · Camera · GPS · Weather · Music · Digital Human · ..."]
    svc["Service Layer<br/>AudioService · GpsService · SdCardManager · MCP Server"]
    proto["Protocol Layer<br/>WebSocket · MQTT+UDP · OpenClaw HTTP API"]
    board["Board Abstraction<br/>DualNetworkBoard · Display · AudioCodec · Backlight · Gauge"]
    drv["Driver Layer<br/>MIPI-DSI · MIPI-CSI · I2S · SDMMC · I2C · UART · IOExpander"]

    subgraph hw["Hardware"]
        direction LR
        p4["ESP32-P4 Host<br/>Main MCU · UI · Audio/Video · Camera"]
        c5["ESP32-C5 Slave<br/>Wi-Fi SDIO"]
        nt26["NT26 4G<br/>Cellular"]
    end

    cloud["OpenClaw Cloud<br/>ASR · LLM · TTS · Agent Orchestration"]

    ui --> apps --> svc --> proto --> board --> drv --> hw
    proto <--> cloud

flowchart LR
    speak["User speaks"] --> mic["I2S microphone"]
    mic --> sr["ESP-SR wake-word / VAD"]
    sr --> enc["AudioService encodes"]
    enc --> link["WebSocket / MQTT"]
    link --> asr["Cloud ASR"]
    asr --> llm["LLM"]
    llm --> tts["TTS"]
    tts --> rx["Device receives audio stream"]
    rx --> spk["I2S speaker playback"]
    rx --> lvgl["LVGL UI updates<br/>chat bubbles / chat emotion EAF / digital-human expressions"]

Metalio Claw4 uses an ESP32‑P4 + ESP32‑C5 heterogeneous dual‑chip design, communicating via Espressif’s ESP‑Hosted framework:

flowchart TB
    p4["ESP32-P4 Host<br/>LVGL UI · Audio/Video · Camera · GPS / Sensors"]
    c5["ESP32-C5 Slave<br/>Wi-Fi STA/AP · Network Stack"]
    nt26["NT26 4G Module<br/>LTE Cellular"]

    p4 <-->|"SDIO 4-bit<br/>CMD=50 CLK=51 D0=49<br/>D1=34 D2=31 D3=53<br/>RESET=54"| c5
    p4 -->|"UART<br/>TX=28 RX=29 MRDY=13 SRDY=4"| nt26

ESP32‑P4 lacks native Wi‑Fi RF, thus needs the C5 coprocessor. Wi‑Fi and 4G are unified under DualNetworkBoard, selectable in the Network Configuration app.

Pin definitions source: main/boards/metalio-claw-4/config.h
IO extender mapping source: main/boards/common/IOExpander.hpp
P4 ↔ C5 SDIO pins: defined in sdkconfig via CONFIG_ESP_HOSTED_SDIO_* (P4 host side configurable; C5 slave side fixed by IOMUX).

Metalio Claw4 connects P4 and C5 via SDIO Slot 1, 4‑bit bus at 40 MHz clock. P4 host‑side pins are configured in sdkconfig; C5 slave‑side pins are fixed by the chip’s IOMUX and cannot be changed in software.

P4’s default Slot 1 pins are CLK=18 / CMD=19 / D0‑D3=14‑17. Metalio Claw4 uses the pins above due to PCB layout; after changing P4 pins you must recompile and flash both the P4 main firmware and the C5 coprocessor firmware (C5 pins must match hardware).

flowchart LR
    subgraph p4["ESP32-P4"]
        direction TB
        i2cBus["I2C GPIO 7/8"]
        i2s["I2S GPIO 9/10/11/12"]
        dsi["MIPI-DSI"]
        csi["MIPI-CSI"]
        sdmmc["SDMMC 4-bit"]
        uart0["UART0"]
        uart2["UART2"]
        uart4g["UART + MRDY/SRDY"]
        sdio["SDIO Host"]
    end

    mic["I2S Mic"] --> i2s
    i2s --> spk["I2S Spk"]
    dsi --> lcd["720x720 LCD"]
    dsi --> touch["GT911 Touch"]
    i2cBus --> tca["TCA9555"]
    i2cBus --> bq["BQ27220"]
    i2cBus --> nu["NU1680"]
    i2cBus --> qmc["QMC6309"]
    tca --> gpsPwr["GPS power"]
    tca --> camPwr["CAM power"]
    tca --> btPwr["BT power"]
    tca --> pwr4g["4G power"]
    tca --> sdPa["SD / PA"]
    csi <--> ov["OV2710 Camera"]
    sdmmc <--> sd["microSD"]
    uart0 <--> gps["GPS Module"]
    uart2 <--> bt["BT Audio Module"]
    uart4g <--> nt26["NT26 4G"]
    sdio <--> c5["ESP32-C5 Wi-Fi"]

(The original document left this section blank; keep it as‑is.)

Metalio Claw4 firmware is based on the XiaoZhi AI (xiaozhi-esp32) framework, customized for the metalio-claw-4 board.

Application tracks device state:

stateDiagram-v2
    [*] --> starting
    starting --> configuring
    configuring --> idle
    idle --> connecting
    connecting --> idle
    connecting --> listening
    listening --> speaking
    speaking --> listening
    speaking --> idle
    idle --> upgrading
    idle --> activating
    connecting --> fatal_error
    upgrading --> idle
    activating --> idle

• idle – waiting for wake‑word
• listening – recording, streaming ASR upstream
• speaking – playing TTS response
• connecting – establishing WebSocket / MQTT link

In metalio-claw-4.cc constructor:

flowchart TD
    s1["1. I2C bus GPIO 7/8"] --> s2["2. TCA9555 IO expander<br/>power peripherals; PA after ~8s; CAM/SD default off"]
    s2 --> s3["3. BQ27220 fuel gauge + low-voltage protection"]
    s3 --> s4["4. Bluetooth audio UART + default mode 1"]
    s4 --> s5["5. SD mount + virtual USB worker<br/>USB Serial/JTAG by default"]
    s5 --> s6["6. MIPI-DSI LCD"]
    s6 --> s7["7. GT911 touch"]
    s7 --> s8["8. LVGL display adapter"]
    s8 --> s9["9. NU1680 wireless-charge detect task"]
    s9 --> s10["10. System monitor CPU / RAM / battery"]
    s10 --> s11["11. I18n::Init read NVS locale<br/>after NVS ready in main.cc"]

main/
├── application.cc              # Startup, state machine, protocol routing
├── i18n/                       # Runtime UI locales (catalog.json)
├── boards/metalio-claw-4/      # Metalio Claw4 board init
│   ├── config.h                # GPIO pins, screen params
│   ├── config.json             # Build config
│   └── metalio-claw-4.cc       # Board entry point
├── display/screen/             # LVGL apps (incl. settings / standby / test / sd_card)
├── audio/                      # Capture, playback, wake‑word
├── protocols/                  # WebSocket / MQTT
└── boards/common/              # Common drivers (GPS, SD, fuel gauge, usb_virtual_disk, …)

esp_claw_bin/                   # ESPClaw (ota_1) companion images & flash notes
partitions/v1/32m_dual.csv      # 32 MB dual-system table (ota_0=main FW, ota_1=ESPClaw)

OpenClaw is Metalio’s cloud AI Agent platform. The device talks to it through HTTP API:

API base defined in main/api_endpoints.h.

The device‑side OpenClaw App (openclaw_screen) provides:

• Hold‑to‑talk to send voice commands
• Message‑bubble chat UI
• Multi‑turn dialogue with the cloud Agent

Unlike cloud OpenClaw, the home‑screen ESPClaw entry boots the local edge_agent flashed in ota_1 (emote / system / storage partitions are also required):

• Tap home ESPClaw → after confirm, switch boot partition to ota_1 and reboot
• If ESPClaw images were never flashed, the UI reports ESPClaw not found
• Flash guide & full image list: esp_claw_bin/README.md; partition‑table offset must be CONFIG_PARTITION_TABLE_OFFSET=0x9000

Home‑screen app list (home_screen.cc → kApps[]):

• Language: Runtime switch Simplified Chinese / English (I18n::SetLocale, NVS); home rebuilds after change
• Standby: Configure “enter standby” and “cumulative shutdown” (minutes; 0 = disable)
• Bluetooth: Former standalone Bluetooth Config lives here (modes 1/2/3, scan & pair, Reset Bluetooth)
• Volume and backlight are also here (no separate home Backlight icon)

Factory / stress entry (test_screen): auto tests (fuel gauge / wireless charge / camera, …), stress test (LVGL + BGM + motor + camera loop), hardware checks. Everyday users can ignore this.

• Header toggles Chat / Emotion modes
• Chat mode: left/right text bubbles (assistant/system left, user right)
• Emotion mode: plays SD‑card EAF animations at /sdcard/system/chat/{emotion}.eaf (server emotion name; must match [A-Za-z0-9_-]); one shared white caption at the bottom shows the latest message
• Requires the SD card and files under that directory; emotion mode is unavailable without them

• Network HLS (m3u8) live streams; built‑in station table (radio_stations.h)
• Spectrum visualization while playing; entering the page pauses the system voice path and restores wake‑word on exit
• Prefer Wi‑Fi; 4G uses a lot of data (UI shows a warning)

• Requires SD card: if unmounted, only a hint is shown
• Record tab: start / stop with timer; saves Ogg Opus to /sdcard/recordings/REC_*.opus (much smaller than PCM WAV)
• List tab: lists .opus (legacy .wav still supported); tap opens a detail page (does not play immediately)
• Detail: play / stop; Transcribe uploads the file as multipart to POST /api/v1/asr/transcribe (X-Device-Id) and shows full text, duration, dialogue lines, and summary
• API base paths live in main/api_endpoints.h (kAsrTranscribe)

ESP32‑P4 talks to the Bluetooth codec via UART (115200, GPIO 26/27) using AT commands to switch work modes; hardware overview see §2.4. Bluetooth UART and BT_POWER pin appear in §7.1 and §7.3.

Think of the Bluetooth chip’s three modes as three tasks: (1) everyday XiaoZhi chat, (2) talk via Bluetooth ear‑/speaker, (3) use phone as remote to play music. Most switches are handled automatically by firmware.

Mode 1 – Daily XiaoZhi Chat (boot default)
Device powers up in mode 1, the default for normal voice interaction. The Bluetooth codec routes I2S for XiaoZhi’s mic & speaker; you just wake‑word → chat. Exiting the Music app automatically returns to mode 1.

Mode 2 – External Bluetooth Device for XiaoZhi Chat
To chat via a Bluetooth headset or speaker (must have a mic), open Settings → Bluetooth, select Mode 2, scan, pair. Audio routes to the paired device. Return to mode 1 by manually switching back on the same tab.

Mode 3 – Phone → Device as Bluetooth Speaker
Open the Music app → firmware auto‑switches to mode 3 (speaker‑waiting). Connect phone via Bluetooth, play music from any app; song info and (if supported) lyrics appear on screen. Leaving the Music app restores mode 1 automatically.

Switching requires a preceding AT+RX / AT+TX then a ~700 ms delay before AT+MODE. Firmware handles the delay in a background task.

Successful switch replies with SET MODE 1 / SET MODE 2 / SET MODE 3.

Automatic Switch Triggers (firmware behavior)

After switching to Mode 2 in Settings → Bluetooth, you can use these AT commands (the remote device must have a mic for voice chat).

After a successful link, Mode 2 panel lets you toggle audio profile:

Entering the Music page auto‑sets Mode 3; the screen shows song title & scrolling lyrics (3‑line). Buttons map to AT commands:

Settings → Bluetooth → Reset Bluetooth pulls low/high on BT_POWER via the IO extender, power‑cycling the Bluetooth module into download mode. Use only when flashing Bluetooth firmware; normal operation does not need it. See §14.5.

Official docs (recommended first read):
ESP32‑P4 Getting Started — ESP‑IDF v5.5.4

Linux/macOS quick install:

git clone -b v5.5.4 --recursive https://github.com/espressif/esp-idf.git
cd esp-idf
./install.sh esp32p4
. ./export.sh

Windows: follow the official Windows toolchain guide or use WSL2 with the Linux steps.

Verify installation:

idf.py --version

git clone https://github.com/CloudZao/MetalioClaw4.git
cd MetalioClaw4

The repo ships with a ready‑to‑use sdkconfig; after cloning you can run idf.py build directly—no idf.py set-target needed. See §14.2 for sdkconfig notes.

Tip: With a ready ESP‑IDF environment, just run idf.py build (§14.1). sdkconfig details in §14.2.

# Ensure ESP‑IDF environment is sourced
. ~/esp-idf/export.sh   # adjust path as needed

# Direct build; no set‑target required
idf.py build

Output artifacts appear in the build/ directory.

Do not edit sdkconfig casually. It is already tuned for Metalio Claw4 hardware (ESP‑Hosted SDIO Wi‑Fi coprocessor, MIPI‑DSI display, PSRAM, etc.). Arbitrary changes may break boot, display, Wi‑Fi/4G, camera, or SD‑card init.

If customization is needed, prefer adding overrides via sdkconfig.defaults or the board‑level config.json field sdkconfig_append.

When plugged in and powered, the device typically presents four serial ports. Port names (e.g., COM3, /dev/ttyUSB0) may vary; identify them by their descriptors:

Tip: P4 ↔ Bluetooth everyday communication uses on‑board UART (GPIO 26/27); flashing the Bluetooth chip needs the CH340K USB port. For 4G AT debugging, use the port described as at. Close idf.py monitor before enabling virtual USB; reopen the monitor after disabling it.

Replace /dev/ttyACM0 with the port showing descriptor “USB JTAG/serial debug unit”.

# Flash + live log
idf.py -p /dev/ttyACM0 flash monitor

monitor opens a serial log; quit with Ctrl+].

Flash‑only:

idf.py -p /dev/ttyACM0 flash

Log‑only:

idf.py -p /dev/ttyACM0 monitor

The Bluetooth audio codec has its own USB‑UART (CH340K). Flashing must use that port, not the P4 JTAG port.

Steps:

1. Plug in USB, power the device. Locate the port whose descriptor is USB Serial (CH340K).
2. Open your Bluetooth‑flash tool and select that CH340K port.
3. Put the Bluetooth module into download mode:
   • From the home screen, open Settings → Bluetooth and tap Reset Bluetooth; or power‑cycle the device.
   • The module will enter download mode, ready for flashing.
   • If the flash tool cannot see the device, repeat step 3 then retry.
4. After flashing, again tap Reset Bluetooth or power‑cycle to boot with the new firmware.

“Reset Bluetooth” toggles BT_POWER via the IO extender, cutting then restoring power to the Bluetooth chip. Use this only for firmware flashing or maintenance; normal operation does not require it.

Assets for features like the Digital Human are in the sd_images/ folder. Copy the contents to the root of a FAT‑formatted SD card, preserving the directory structure. Details are in sd_images/README.md.

Common paths:

The device can expose microSD as USB Mass Storage to a PC (usb_virtual_disk, TinyUSB MSC):

1. Confirm the SD card is inserted and the SD Card app shows it mounted.
2. Open SD Card → tap Enable virtual USB.
3. After the PC mounts the drive, copy files; the same USB port is no longer Serial/JTAG — stop flashing/monitoring first.
4. Eject / safely remove on the PC, then tap Disable virtual USB; or leave the SD Card page (auto force‑disable and best‑effort restore of serial).

If disable fails, eject the drive on the PC first to avoid filesystem corruption.

Before using home ESPClaw, Flash must follow partitions/v1/32m_dual.csv and include edge_agent / emote / system / storage images from esp_claw_bin/.

Recommended: flash the main firmware and ESPClaw‑related bins in one full pass. Naming convention and esptool examples:

• esp_claw_bin/README.md

Partition‑table offset must be 0x9000 (same as edge_agent).

After board init, a background task prints CPU usage, free memory, and battery status each second—handy for performance/power analysis.

• Home Pin Test: quick GPIO / peripheral connectivity check (pin_test_screen).
• Home Test: factory entry (auto test, stress test, hardware tests, … — test_screen).

Q: Compilation complains about ESP‑IDF version mismatch
A: Make sure you are using ESP‑IDF v5.5.4 and have sourced the environment (./export.sh) before each build.

Q: Screen stays dark
A: 1. Verify sdkconfig has not been edited accidentally. 2. Check MIPI‑DSI LDO supply (channel 3, 2500 mV). 3. Confirm screen driver: default NV3051F; alternate FL7707N via METALIO_CLAW_4_USE_FL7707N macro.

Q: Wi‑Fi not scanning
A: Metalio Claw4 gets Wi‑Fi via ESP‑Hosted SDIO to the ESP32‑C5 coprocessor. If the C5 firmware isn’t flashed or the SDIO link is faulty, Wi‑Fi won’t work. Refer to the Dual‑Chip Architecture and Peripherals and Pins sections to verify wiring and firmware.

Q: 4G fails to register
A: 1. Ensure you switched to 4G mode in the Network Configuration app. 2. Confirm the internal 4G patch SIM or external SIM is active and not overdue. 3. For external SIM, check it is properly inserted. 4. Watch the NT26 module’s AT+CEREG status in the serial log.

Q: Phone app can’t dial
A: The internal SIM supports data only. Insert an external SIM, switch to it in Network Configuration, then use the Phone app. See §2.4 4G & SIM Card.

Q: Wi‑Fi / base‑station positioning unavailable
A: These require the device to be in 4G network mode with the module successfully registered. Refer to §2.4 4G‑Assisted Positioning.

Q: SD‑card mount fails
A: 1. Check the SD card is FAT32 formatted. 2. Verify external power to the SD‑card slot: the IO extender pin SD (P0‑3) must be low to enable; firmware drives it low on boot. 3. Ensure the SDMMC PHY power domain is enabled (see config.h SDMMC_LDO_CHAN_ID, default LDO chan 4); SdCardManager requests it at mount time. 4. If the log shows Failed to create SD power control driver, the power domain isn’t ready. 5. Confirm SDMMC pins match config.h.

Q: Home screen enters standby / powers off after a few minutes idle
A: Expected behavior – configurable under Settings → Standby; see §2.5 Power & Battery Life.

Q: Screen suddenly turns blue (blue‑screen)
A: A blue screen indicates a firmware crash; the device auto‑reboots. After reboot you should see the animation and return to the home screen. If blue‑screens recur, connect the serial log to inspect the crash details, ensure you are running the latest firmware, and if the issue persists, file an issue.

This document tracks firmware revisions. Should you notice any mismatch between the descriptions here and the actual hardware, please submit an Issue.