This issue was actually first reported on an internal forum but applies to the public project ".
Version 0.0.3.
Symptom is that on boards using RMII mode (ex. RM46 Control Card) - the lwip demo does not work and no packets appear to be transmitted.
The issue is simply that RMIISPEED was not set by the updated example code. See the wiki page for a patch to correct the issue... it is listed on the bottom of the page under "Known Issues".