I'm having the same issue. I compiled successfully but just get the unexpected block error.
I've tried somagic and the capture device on a laptop running Mint and all works fine (although I only tested it for a few minutes), so it's not a dud device.
I noticed there was a discussion here:
https://groups.google.com/forum/?fromgr ... 6YOygTXtqs
about running somagic on the Raspberry Pi, which suggests it's a Pi or ARM issue, possibly specific to the Pi kernel.
I have wondered if it's a power issue, perhaps the Pi's USB ports aren't giving enough power. Might be worth trying it with a decent powered hub.
In the mean time I'm looking for other Easycaps, there are at least 4 versions of these all with different chipsets, with different levels of Linux support. More info here: