Thanks for making that clear to me. I really couldn't imagine that people have worked with these kind of lags for the past five years ;-)
I'm using the latest available firmware for Tera1 CPUs (4.5.1) and yes, I can confirm that the network endpoint is okay. An old Asus eee-Book outperformed the Tera1 client on the same switch port without any problems.
Strangely I've just noticed that somehow now it working quite well at the moment. And for the first time, I see "real" values on the device's internal webserver for Roundtrip latency and Pipeline bandwidth.
The last days there was just a "0".
Maybe the device is really broken :-(