Milk-V Meles Image Flashing Guide

This page describes the Linux workflow for flashing images to Milk-V Meles. Use the links below for other devices or operating systems.

Other Flashing Tutorials	Link
Lichee Pi 4A (Linux)	Linux flashing guide
Lichee Pi 4A (Windows)	Windows flashing guide
Milk-V Pioneer	Flashing guide

warning

Before you proceed, compare your board against the reference image and make sure the hardware matches.

Demonstration Environment

All steps were validated under the following environment:

• Operating system: Ubuntu 22.04.5 LTS
• Architecture: x86_64
• Milk-V Meles configuration: 8 GB RAM
• Python version: 3.10.12

If you follow this procedure in the same environment and encounter issues, submit an issue via the support page.

warning

Python versions newer than 3.12 may fail when writing the bootloader to SPI NOR flash. Use Python 3.11 or earlier.

Tool Installation

The following packages are required for downloading and flashing images. Install them before continuing.

Download Utility

In a desktop environment you can download images from the mirror via a browser. For command-line downloads we use wget.

wget --version

If wget is missing, install it:

sudo apt install wget

sudo prompts for your password. Ensure you know it; this reminder will not be repeated later.

Archive Utility

.zst archives can be unpacked with zstd, tar, or 7z. This tutorial demonstrates the zstd command-line tool. Confirm whether it is installed:

zstd --version

If no version is shown, install zstd:

sudo apt update
sudo apt install zstd

Boot Options

Milk-V Meles supports two boot paths: booting from an SD card and booting from eMMC. Choose the method that fits your scenario.

warning

Flashing erases existing data. Back up important files before you begin.

Before tackling either boot mode, ensure that the SPI NOR flash holds the correct firmware. The next section explains how to program it.

Flash the SPI NOR Firmware

Milk-V Meles relies on its SPI NOR flash to store the bootloader that brings up the system and exposes the SoC download mode. The SoC cannot boot directly from MicroSD or USB.

If you replace the SPI NOR device or the firmware becomes corrupted, reflash the bootloader via a serial connection. Wiring instructions are available in the official hardware documentation; connect TX ↔ RX and GND ↔ GND between the board and host.

Preparation

Install Yoctools:

sudo pip install yoctools -U

If pip is unavailable, install it first:

sudo apt install python3-pip

Verify the installation:

yoc --version

Download the image writer utility:

wget https://github.com/milkv-meles/thead-bin/raw/main/image-writer/iw-single-line.bin

Download the U-Boot binary that matches your board:

• 8 GB model: u-boot-with-spl-meles.bin
• 16 GB model: u-boot-with-spl-meles-16g.bin

Example (8 GB board):

wget https://fast-mirror.isrc.ac.cn/revyos/extra/images/meles/20250323/u-boot-with-spl-meles.bin

Write the Bootloader to SPI NOR Flash

1. Determine the serial port device (commonly /dev/ttyUSB0).
2. List available devices with cct:

sudo cct list -u /dev/ttyUSB0

The program waits for the board to respond. Connect the USB-to-TTL adapter, wire TX ↔ RX and GND ↔ GND, press and hold the download button, power the board via USB Type-C, then release the button. The storage list should appear:

Memory device list:
  dev = ram0   , size =    1.1MB
  dev = qspi0  , size =   16.0MB

3. Load the image writer into SRAM:

sudo cct download -u /dev/ttyUSB0 -d ram0 -f iw-single-line.bin -v checksum -r

Wait for the transfer and checksum to complete.

4. Flash the U-Boot binary to SPI NOR (adjust the file name if you use the 16 GB image):

sudo cct download -u /dev/ttyUSB0 -d qspi0 -f u-boot-with-spl-meles.bin -v checksum -r -t 1200

A progress indicator appears; the operation typically finishes within a minute. After the checksum passes, the SPI NOR flash is updated.

You can now proceed with either boot method.

Boot from SD Card

Hardware Preparation

Prepare a MicroSD card reader and a MicroSD card. Because compatibility varies, refer to the tested card list.

If flashing or booting fails with an unlisted card, submit an issue and consider using the eMMC method instead.

Obtain the SD Card Image

Download the SD card image (prefixed with sdcard-meles-) from:

• RevyOS 20240720 (Kernel 5.10)
• Latest release (Kernel 6.6): 20251226

Example for RevyOS 20250323:

wget https://fast-mirror.isrc.ac.cn/revyos/extra/images/meles/20250323/sdcard-meles-20250323_154525.img.zst
unzstd sdcard-meles-20250323_154525.img.zst

The extraction generates sdcard-meles-20250323_154525.img.

Writing Options

Choose one of the following methods to write the image to the SD card:

BalenaEtcher

Download BalenaEtcher from https://etcher.balena.io/ and install the Linux x64 build.

1. Insert the SD card.
2. Launch BalenaEtcher.
3. Click Flash from file and select the image.
4. Select the target device.
5. Click Flash and wait for completion.

dd

1. Identify the device node (/dev/sdX or /dev/mmcblk0) using lsblk.
2. Unmount any mounted partitions:

sudo umount /dev/sdX1

3. Flush pending writes:

sudo sync

4. Write the image (replace sdX with the correct device):

sudo dd if=sdcard-meles-20250323_154525.img of=/dev/sdX bs=4M status=progress
sudo sync

Ensure the card is unmounted before removing it.

Boot from SD Card

Insert the SD card into the slot shown below and power on the board.

Boot from eMMC

Ensure the eMMC module is installed on the back of the board before flashing.

Obtain the eMMC Images

Download the following files:

• RevyOS 20240720 (Kernel 5.10)
• Latest release (Kernel 6.6): 20251226

Required files:

• u-boot-with-spl-meles*.bin — U-Boot binary
• boot-meles-*.ext4.zst — boot partition
• root-meles-*.ext4.zst — root partition

Example (20250323):

wget https://fast-mirror.isrc.ac.cn/revyos/extra/images/meles/20250323/u-boot-with-spl-meles.bin
wget https://fast-mirror.isrc.ac.cn/revyos/extra/images/meles/20250323/boot-meles-20250323_154525.ext4.zst
wget https://fast-mirror.isrc.ac.cn/revyos/extra/images/meles/20250323/root-meles-20250323_154525.ext4.zst
unzstd boot-meles-20250323_154525.ext4.zst
unzstd root-meles-20250323_154525.ext4.zst

Install Fastboot

Check whether fastboot is available:

fastboot --version

If not, install it:

sudo apt install fastboot

Flash the eMMC

1. Enter download mode:
   • Hold the download button on the board.
   • Connect a USB Type-C cable from the power port to the host.
   • Release the button.
2. Confirm that lsusb lists ID 2345:7654 T-HEAD USB download gadget.
3. Flash the images:

fastboot flash ram u-boot-with-spl-meles.bin
fastboot reboot
sleep 3
fastboot flash boot boot-meles-20250323_154525.ext4
fastboot flash root root-meles-20250323_154525.ext4

After flashing, reboot to start from eMMC.

Troubleshooting

Weak Wi-Fi Signal on the Latest Kernel

When using the latest RevyOS kernel (6.6.82 at the time of writing), the board defaults to an external antenna. Without an antenna connected to the IPEX connector, Wi-Fi performance degrades significantly.

Use gpiod to switch to the onboard antenna:

sudo apt update && sudo apt upgrade -y
sudo apt install -y gpiod
sudo gpioset 5 24=1

warning

Reapply the GPIO setting after each reboot.

User Credentials

Default login credentials:

• Username: debian
• Password: debian

Change the password immediately after the first login for security.