Tuesday, December 30, 2014

ARCH Linux on a WM8850-based mini laptop

One of my purchases earlier this year was a mini laptop, powered by a Wondermedia WM8850 chip.

It's kinda handy: runs Android/Linux selectively, has a HDMI interface, wired Ethernet and fullsize USB 2.0 ports. Also, it can be charged from USB, tablet style.

Quirks include no HDMI on Linux (yet), and it takes a bit of effort to turn on the wireless. Missing the gpio binary, you can get there by using the sysfs interface:

echo 6 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio6/direction
echo 1 > /sys/class/gpio/gpio6/value

Just echo 0 there to turn it off again.

Compiling a kernel needed some scraping on the web, but can be done like this:

cd linux-3.16
nice make ARCH=arm menuconfig
nice make ARCH=arm zImage
cat arch/arm/boot/zImage arch/arm/boot/dts/wm8850-w70v2.dtb > arch/arm/boot/zImage_w_dtb
mkimage -A arm -O linux -T kernel -C none -a 0x8000 -e 0x8000 -n "My Linux" -d arch/arm/boot/zImage_w_dtb ~/uzImage.bin
make ARCH=arm modules
sudo make ARCH=arm modules_install

The kernel config is online here.

It works happy with a 8GB SD card and adding a bit of swap can't hurt as the 512MB of RAM is not that much.

Thanks for the vt8500 developers!


  1. hi, can u put a step by step for make the kernel and get ready the arch in wm8850? tanks for all.

  2. The commands to make the kernel are up there, they should work with a 3.16 kernel from kernel.org.
    As for Arch, I think it was a simple download, extract tarball to SD card.
    The only tricky part was the bootloader, I'll post that later.