I have the 3m509 network card and the system won't bring it up upon startup. According to manprode man page, I typed 'manprode 3m509.o io=300 irq=10' and it returned an error. After several trial and error, I found that the io=300 would not be accepted. It works when I type 'manprode 3m509.o irq=10' only. Shutting down and bringing up the system again, eth0 still fails. Having looked into the configuration file, io=300 is there. Removing io=300 and all subsequence rebootings have the eth0 up properly.
You need io=0x300, not io=300.