DevTerm A04 Debian Image

This project builds a ready-to-use Debian 13 Linux image for the ClockworkPi DevTerm A04. The A04 is a small computer with an Allwinner H6 chip and a 480x1280 screen.

The image is live. It is not an installer. You write it to a TF/microSD card, put the card in the DevTerm, and turn the device on. On the first boot, the system makes the root filesystem use the rest of the card.

What you get

• Debian 13 (trixie) for 64-bit ARM.
• A text console with kmscon.
• Ly, a text login screen, running inside kmscon.
• Starship as the default prompt, using the image's Paper Mono Nerd Font/Powerline glyphs.
• Paper Mono Nerd Font at a 16 px / 8x16 cell size as the console font.
• Every NerdFont from your font folder, installed for all programs.
• Two text-mode browsers, both usable without X or Wayland: Carbonyl (Chromium) and Chawan (small Nim engine).
• Wi-Fi, SSH, Tailscale, sound, fan control and the 58 mm thermal printer.
• Yazi, a fast terminal file manager (text previews; optional preview tools can be installed from apt).
• tmux configured with a Ctrl-a prefix and a clickable Wi-Fi status section (with live Tailscale status) that opens the NetworkManager TUI.
• The special ClockworkPi A04 kernel. Debian kernel packages are pinned so a normal apt update && apt upgrade cannot replace it by accident.

The A04 panel, backlight, sound codec and printer pins need the vendor Linux 5.10 kernel. A normal Debian kernel does not support them yet.

First boot

Use a card larger than 4 GiB. An 8 GB, 16 GB or 32 GB card is a good choice.

1. Flash the image to the card.

2. Put the card in the DevTerm.

3. Turn it on.

4. Wait for the first boot. devterm-growroot.service grows the root partition and filesystem to fill the card.

5. Log in with:

   user: devterm
   pass: devterm
   

   The root password is also devterm. Change both passwords.

The Ly login screen shows the users. Pick devterm, type the password, and choose the Shell session. You then get a normal Linux shell.

Build it

You need:

• a Linux PC with an x86_64 CPU
• Podman, with arm64 container support
• about 25 GB of free disk space
• internet access
• Python 3 with Pillow and fontTools
• the font folder at ~/Sync/Fonts (or set DEVTERM_FONT_DIR)

Build everything:

./build.sh

Or run the steps one at a time:

make fetch     # download sources, packages, fonts and browsers
make uboot     # build TF-A and U-Boot
make ly        # build the Ly login screen
make chawan    # build Chawan
make kmscon    # kmscon with the A04 guard band
make rootfs    # build the Debian root filesystem
make image     # make the card image
make verify    # check the image

The first build takes a while because it builds an arm64 Debian system, Ly and Chawan. Later builds reuse cached downloads and build trees.

When it finishes, the flashable files are:

artifacts/devterm-a04.img.zst
artifacts/devterm-a04.img
artifacts/SHA256SUMS

The .img.zst file is about 750 MiB. The uncompressed image is 4 GiB.

Flash the card

Check the card device name first. This command destroys everything on the target card:

zstd -dc artifacts/devterm-a04.img.zst |
  sudo dd of=/dev/sdX bs=4M status=progress conv=fsync

You can also decompress the image and use balenaEtcher or Raspberry Pi Imager.

Project layout

containers/   container files used to build U-Boot, Debian and Ly
overlay/      files copied into the Debian system
scripts/      build and verification scripts
vendor/       U-Boot board files
docs/         kernel and hardware notes
artifacts/    built image and downloaded files (not committed)

More information

• BUILD.md explains the build in more detail.
• USAGE.md explains Wi-Fi, the browser, the printer, fonts and recovery.
• docs/KERNEL.md explains why the image uses the vendor kernel.
• docs/HARDWARE.md has notes about the A04 hardware.

Important notes

• This image is only for the DevTerm A04. Do not use it on the A06, CM4 or RISC-V models.
• The vendor kernel is Linux 5.10.75. It does not get Debian kernel security updates.
• No physical A04 was available while the image was built. The image layout, filesystem, U-Boot boot files, kmscon/Ly setup and package pins were checked, but the first real boot should be treated as hardware bring-up.
• Change the default passwords before putting the device on a network.