Debian for Wondermedia WM8505 Netbooks

This project delivers a complete, modern Debian build for WM8505-powered netbooks. It has been specifically tested for the Sylvania SYNET07526, the sub-$100 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 used is a Linux 6.1 rebase of linux-vtwm, a repository with patches for VIA/Wondermedia SoCs. The build script automatically rebases further to the latest 6.1.x release from upstream, fetches the linux-config-6.1 package from Debian, and adapts the most similar target, config.armel_none_marvell, to be compatible with the netbook using a combination of options from the seed and the kernel's defconfig. multistrap is used to build the Debian root filesystem, and systemd-nspawn to configure it.

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 have been unable to test the WM8650 since I only have WM8505 devices. The kernel options should be the same, so I would expect it to work after changing wm8505-ref.dtb to wm8650-mid.dts in the build script. The wm8505fb.patch would likely need to be reverted as well since WM8650+ uses a different pixel format, which can be done by deleting the file from the patch folder. Please reach out if you run into issues or are able to get this working.}

Credits

Special thanks to wh0's bookconfig for providing a Linux 6.1 rebase of the abandoned linux-vtwm project. This would not have been possible without them.

Project Details

Packages: multistrap.conf integrates all of Debian's standard system utilities by explicitly listing priority important and standard packages. It also includes additional packages for Wi-Fi, SSH, and other utilities.
Patches: wm8505fb.patch applies the correct default contrast value for the WM8505.
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.
- 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.
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 /var/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.

Most 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 run better, 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 multistrap. Follow these steps:

Install the necessary packages:

sudo apt install bc binfmt-support bison build-essential curl debian-archive-keyring dosfstools e2fsprogs flex gcc-arm-linux-gnueabi git jq libssl-dev lynx multistrap parted pigz qemu-user-static systemd-container u-boot-tools zerofree

Clone this repository:

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

Run build.sh (needs root privileges):
```
sudo ./build.sh
```

The resulting build files (disk_6.1.X.img.gz and upgrade_6.1.X.tar.gz) are placed in the build directory.

Releases

Pre-compiled builds are available on the Releases page.

disk_6.1.X.img.gz - Full disk image containing boot and rootfs partitions. Used for new installations.
upgrade_6.1.X.tar.gz - Tarball containing updated boot files and kernel modules to be placed into rootfs. 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_6.1.X.img.gz.
An imaging tool like balenaEtcher (recommended) or dd.

Installation Steps:

Image the SD Card:
- With balenaEtcher: Use balenaEtcher to flash disk_6.1.X.img.gz to your SD card. It will decompress the image for you.
- With dd:
  - Decompress the image with:
```
gzip -d /path/to/disk_6.1.X.img.gz
```
  - Identify your SD card device (e.g., /dev/sdX), and run:
```
sudo dd if=/path/to/disk_6.1.X.img of=/dev/sdX bs=1M status=progress
```
  - Then eject the SD card using:
```
sudo eject /dev/sdX
```
Insert the SD Card: Place the imaged SD card into your netbook.
Boot the Netbook: Turn on your netbook. It will boot from the SD card automatically.

Upgrading

For upgrading an existing Debian installation to a newer kernel.

Requirements:

An SD card with an existing image.
A copy of upgrade_6.1.X.tar.gz.
A Linux computer.

Upgrade Steps:

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
```

Update the boot partition:

sudo rm -rf boot/*
sudo tar -xzvf /path/to/upgrade_6.1.X.tar.gz -C boot --strip-components=1 boot

Update the rootfs partition:

sudo rm -rf rootfs/lib/modules/*
sudo tar -xzvf /path/to/upgrade_6.1.X.tar.gz -C rootfs --strip-components=1 --skip-old-files rootfs

Eject the SD card:
```
sudo eject /dev/sdX
```

lrussell887 / Debian-for-WM8505-Netbooks