So my next piece of work on the Vocore was to mount the filesystem from a USB stick. I found some instructions here. So I started adding all the necessary kernel modules, hoping that it would be as simple as getting the USB soundcard to work. It wasn’t quite that easy. I thought that I had done everything, but just got strange messages when I tried to mount the disk. Then I found this helpful link.
It described exactly what I was seeing. In short, you can’t rely on the error messages being returned by mount on OpenWrt. So to diagnose the problem, the most important thing was using the
logread command to get some ideas why the USB drive was not mounting. In my case (I was mounting a vfat formatted thumbdrive) I needed to add support for Codepage 437 and ISO 8859–1 into the kernel. So when building OpenWrt, I needed to go into Kernel Modules -> Native Language Support, like this:
But both those character set problems were quite clear from the log entries, so working out what I needed to do wasn’t that difficult … once I knew that I should not trust the error messages being returned by mount.
And I did find some more detailed information about filesystems and character set problems here … albeit for a different type of device, but I think the principle is the same.
Anyway, as soon as I added the extra modules for the correct character sets then everything came to life and I could mount the USB disk. Happy days. So now I can play audio files from USB storage, which works great.