hi Alex,
indeed, two things in parellel. I wanted opencv to work, so when I noticed that your prebuilt image was uclibc-with-broken-opencv-as-expected, I went and rebuilt as per Sergey instructions to get eglibc and opencv working. I didn't try to talk to it first using the Linux Arduino IDE, since that is all setup to build eglibc images.
I will have to check if the Arduino IDE (or indeed a vanilla Linux "sz" program) will take to the uclibc image properly just for the fun.
Won't get to that this evening though, but I will definitely check it tomorrow.
Liam