Didn't see the P at first, so I went over to their forums and there seems to be a mixed bag of results. Some of the users have said that they were able to flash with the basic wrt54g firmwares. Here is where the debate begins as some stated that they were able to use the DD-WRT firmware and others were still up in arms. I did find where some have stated that the data throughput of the P version was subapr and they have cascaded it with another router to get acceptabel data throughput. Sorry to get your hopes up, but it doesn't look entirely impossible, but if this is your only router and you need it for the Vonage, then I wouldn't try it for the possibility of losing the Vonage service. I would recommend that you get another router as well and cascade them. If you have the H@H service, you can order the T-Mo routers (either D-Link or Linksys) and get them for free after mail in rebate.