try to make sure eth0 is not up as a possible workaround. so, the command ifconfig should not list eth0 if you're using eth1.
which version of ubuntu are you using? -- Broadcom 43xx requieres modprobe and goes off after some time https://launchpad.net/bugs/68951 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
