This is the next post in my series about upgrading my old Chumby 8’s kernel. Here are links to part 1 and part 2 if you missed them. As a quick summary, I got U-Boot working in part 1 and then got the SD card working in part 2. In this part I’ll describe the complicated process of how I got Wi-Fi working.
The Chumby 8/Insignia Infocast 8 has a built-in AzureWave AW-GH321 802.11g module. This is a pretty old module that doesn’t even support 802.11n, so it maxes out at 54 Mbps and the link is an archive.org link because it’s nowhere to be found these days. The module makes use of the Marvell 88W8686 chipset, which connects through the SDIO bus. SDIO is basically just the same as SD, except it’s for I/O devices like Wi-Fi and Bluetooth modules instead of SD cards. This wireless chipset is supported by a Linux driver called libertas.
This is a continuation of my previous post about upgrading the old 2.6.28 Linux kernel that came with my Chumby 8. In that post, I got a modern U-Boot working with SD card support, which is what I needed in order to boot Linux.
After I finished getting U-Boot working, I began work on the kernel. I based my work on the stable kernel version 5.15.33. I started by compiling a kernel using the bundled pxa168_defconfig file. I created a device tree file called pxa168-chumby8.dts based on pxa168-aspenite.dts. It needed a few tweaks. I specified the correct amount of RAM for the Chumby 8 (128 MB) and changed the model and compatible strings. I also disabled “twsi1” which is an I2C host. I wasn’t ready to deal with I2C yet. Here’s a small snippet of the relevant changed parts of my new device tree file.
As I mentioned in my last post, I spent a good chunk of my spare time over the past 6 months working on a project I’ve been thinking about for over a decade. I bought a Chumby 8 in 2011. It’s an 8″ touchscreen device powered by the Marvell PXA166 processor. It is essentially a souped-up digital picture frame with extra capabilities like speakers, a microphone, and Wi-Fi. There are a bunch of little Flash-based “apps” you can install for stuff like pictures, music, sports scores, weather, games, etc. I have no idea how many of the apps still work these days. Chumby actually went out of business a few months after I bought mine, although one of the founders stepped up to keep the service running. A variant of this device was also created for Insignia, which was called the Infocast 8″ Internet Media Display.
I was never really interested in using it for any of the stock functionality. I thought it would be a fun development platform. It would be exciting to make some custom apps in Qt or something. One thing that was a little frustrating was that it came with a Linux 2.6.28 “Erotic Pickled Herring” kernel circa Christmas 2008, which was ancient even at the time I bought it. This is a pretty common issue with Linux-based devices. I will even admit I’ve been responsible for some old kernels out in the field in Internet-connected devices. I don’t blame Chumby. It’s tough when the SoC vendor doesn’t submit their kernel modifications upstream or at least keep their fork up to date. I’ve been there.
