Debian for Wondermedia WM8505 Netbooks

This project delivers a complete, modern Debian 13 (Trixie) build for netbooks powered by the Wondermedia WM8505 SoC. It was specifically tested on the Sylvania SYNET07526, the sub-$100 Windows CE netbook sold by CVS in 2011. It has been found to work on other generic WM8505 netbooks, and should work on the WM8650 with some adjustments*.

The kernel is a Linux 6.12 rebase of linux-vtwm, a repository with patches for VIA/Wondermedia SoCs. The build script automates the whole process: it updates the kernel to the latest 6.12.x release from upstream, fetches the official armel configuration from Debian, and merges it with custom settings to create a compatible kernel. The Debian root filesystem is built with mmdebstrap.

All standard system utilities and kernel modules are included, providing the functionality you would expect from a stock Debian system. USB sound cards, Wi-Fi adapters, and Ethernet adapters have been tested to work normally.

_{* I only have WM8505 devices, so I haven't been able to test this on a WM8650. The kernel config should be the same, so all you'll need to do is change the device tree target from vt8500/wm8505-ref.dtb to vt8500/wm8650-mid.dtb in build.sh to get it to compile. The contrast patch is specific to the WM8505, so delete patches/wm8505fb.patch. Also edit overlay/etc/udev/rules.d/10-display.rules and change the contrast ATTR value from 128 to 16. These changes are needed because the WM8650+ uses a different pixel format.}

Credits

Special thanks to wh0's bookconfig for maintaining the functionally abandoned linux-vtwm project, all the way up to Linux 6.1. Their work saved a massive amount of effort in getting the kernel to 6.12.

Project Details

• Seed: seed contains the list of kernel configuration options needed to "seed" support for the WM8505, overriding options in Debian's armel_none_rpi config in combination with the kernel's defconfig.
• Bootloader:boot.cmd contains the commands passed to U-Boot needed to load the kernel and boot Debian.
• Patches: wm8505fb.patch applies the correct default contrast value for the WM8505 in the wm8505-fb driver.
• Systemd:
  • expand-rootfs.service - Expands the root filesystem using growpart and resize2fs on first boot.
  • gen-dropbear-keys.service - Generates Dropbear SSH host keys on first boot.
  • update-hosts.service - Updates /etc/hosts with the hostname on first boot.
  • wlan-gpio.service - Uses gpioset to connect/disconnect the built-in USB Wi-Fi adapter.
  • systemd-firstboot.service.d/override.conf - Drop-in file to override prompts for systemd-firstboot.
  • getty@.service.d/override.conf - Delays login screen until expand-rootfs and gen-dropbear-keys have run.
• Udev: 10-display.rules allows control of display contrast in the wm8505-fb driver. The default of 128 is the max value. A reboot is required to change this setting.
• Fstab: Mounts the swap file /swapfile.

Build Details

• First Boot: The first boot process takes about 5 minutes. You will be asked to configure your timezone, set a hostname, and create a root password.
• Storage: The root filesystem is expanded to fit the SD card on first boot.
• Memory: A 256 MB swap file is included in the disk image and is mounted by /etc/fstab on boot.
• Wi-Fi: The built-in Wi-Fi adapter is controlled by GPIO and is enabled on boot. You can configure your network via nmtui. Ensure your network allows 802.11g clients.
• SSH: Dropbear SSH is included, and keys are generated on first boot.

Limitations

• Display: The display backlight is always on and cannot be controlled.
• Graphics: Graphics acceleration is not available. Everything is software-rendered, making screen redraws very expensive. Video playback and most games are not feasible.
• Audio: Built-in audio is non-functional as kernel support for the codec is unavailable.
• Battery: Battery state monitoring is not possible.
• Storage: Internal NAND/serial flash is inaccessible.
• Performance: The WM8505 is very slow. It runs at 300 MHz with a single core, lacking floating-point acceleration, speculative execution, and essentially all features typical of a modern CPU. Running Debian on such a device is more of a novelty than anything.

Many of these limitations are due to using the open-source linux-vtwm kernel rather than utilizing the modifications made by VIA. I would expect projectgus's kernel_wm8505 repo to be more feature complete, particularly when it comes to graphics, though it is an ancient Android-based kernel stuck at 2.6.29. If someone more experienced than me wants to attempt to apply VIA's patches to a newer kernel, you'd definitely get my attention.

Building

Building requires a Debian or Ubuntu-based system due to its use of mmdebstrap. Follow these steps:

1. Clone this repository and navigate to its directory:

   git clone https://github.com/lrussell887/Debian-for-WM8505-Netbooks.git
   cd Debian-for-WM8505-Netbooks/

2. Run build.sh (needs root privileges):

   sudo ./build.sh

The resulting build files (disk-6.12.X-wm8505.img.gz and upgrade-6.12.X-wm8505.tar.gz) are placed in the build directory.

Releases

Pre-compiled builds are available on the Releases page.

• disk-6.12.X-wm8505.img.gz - Full disk image containing boot and rootfs partitions. Used for new installations.
• upgrade-6.12.X-wm8505.tar.gz - Tarball containing updated boot files and kernel modules. Used for upgrading an existing installation.

Installing

For setting up a new Debian installation.

Requirements:

• An SD card between 4GB and 32GB.
• A copy of disk-6.12.X-wm8505.img.gz.
• An imaging tool like Raspberry Pi Imager (recommended) or dd.

Installation Steps:

1. Image the SD Card:
   • With Raspberry Pi Imager:
     • Choose OS:
       • Click "CHOOSE OS", select "Use custom", and open disk-6.12.X-wm8505.img.gz.
     • Choose Storage:
       • Click "CHOOSE STORAGE" and select your SD card.
     • Write:
       • Click "NEXT". Choose "NO" for applying OS customizations, then "YES" to start flashing.
   • With dd:
     • Decompress the image with:

       gzip -d /path/to/disk-6.12.X-wm8505.img.gz

     • Identify your SD card device (e.g., /dev/sdX), and run:

       sudo dd if=/path/to/disk-6.12.X-wm8505.img.gz of=/dev/sdX bs=1M conv=fsync

     • Then eject the SD card using:

       sudo eject /dev/sdX

2. Insert the imaged SD card into your netbook.
3. Turn on your netbook. It will boot from the SD card automatically.

Upgrading

For upgrading an existing Debian installation to a newer kernel.

Automated Upgrade (recommended):

1. Run the following on your netbook (needs root privileges):

   sudo bash -c "$(wget -q -O - https://raw.githubusercontent.com/lrussell887/Debian-for-WM8505-Netbooks/master/upgrade-kernel.sh)"

Manual Upgrade:

Requirements:

• An SD card with an existing image.
• A copy of upgrade-6.12.X-wm8505.tar.gz.
• A Linux computer.

Upgrade Steps:

1. Mount the boot and rootfs partitions. Identify your SD card device (e.g., /dev/sdX), and run:

   mkdir boot rootfs
   sudo mount /dev/sdX1 boot
   sudo mount /dev/sdX2 rootfs

2. Update the boot partition:

   sudo rm -rf boot/*
   sudo tar -xzvf /path/to/upgrade-6.12.X-wm8505.tar.gz -C boot --strip-components=1 boot

3. Update the rootfs partition:

   sudo rm -rf rootfs/lib/modules/*
   sudo tar -xzvf /path/to/upgrade-6.12.X-wm8505.tar.gz -C rootfs --strip-components=1 --skip-old-files rootfs

4. Eject the SD card:

   sudo eject /dev/sdX