the unit automatically plays the last AV source that was playing when the unit is turned off, HOWEVER, the SD card trumps everything. so if you have an SD card in there it will always play first. but if you take the SD card out, then the last source will play. my guess is that since the SD card is used for software updates it is always the first thing to load since this is necessary when preforming a software update.
as for the default city this is something that they actually changed and i dont know why. the F-series would remember the last city you entered. but now the X-series is different. for some reason it always defaults to the state capital. i am in virginia and it always says Richmond. when i travel to maryland for work it always says Baltimore. i dont know why they changed this but they did and as far as I know there is no way around it.