I managed to track down a small patch from the kernel mailing lists for isdn_net.c that fixed the issue for 2.6.24. I believe this propagated into the main kernel a while back.
http://bugzilla.kernel.org/show_bug.cgi?id=9923 -- isdn interface setup fails after gutsy to hardy upgrade https://bugs.launchpad.net/bugs/253203 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
