I just picked up my 08.5 mz3 last Friday. It has the same stereo problem. Talked to the service manager this morning. He told me the service bulletin has been recalled and Mazda NA is researching this issue and a new fix will come up shortly. Can anyone confirm this?
You could ask the folks at Finishline Performance. They post service bulletins for all Mazdas so they could tell you if you want a second opinion.