I am using firmware 1.5.8 and have not had any problems since updating months ago. For about the last month my dynamic domain ip is being changed to 12.0.0.1. I have to force an update, it works for a short time and then resets. I have changed nothing on the router. I disabled the update and have not had the problem but when my IP changes, I will need to be home to force an update. I am using dyndns.com.
Thanks