I am running IDE 1.6.5 r2 and I have 2 identical Sainsmart Megas. Under 1.5.7 both used to show up as Mega COM ports.
A couple of weeks ago I added a LAN connection to a sketch. Up to then I was using IDE 1.5.7 and Mega #1 as a test unit. I could not make a LAN connection with Mega #1 and the Ethernet shield. I switched over to Mega #2 and was immediately able to make a LAN connection. I tried a few more times with Mega #1 and concluded there was a problem with Mega #1.
In the meantime I have upgraded to IDE 1.6.5 r2. I did note that I had to manually install the Arduino driver for my Uno the first time I used it. It normally shows up as COM 27 (Arduino Uno). After that when I used Mega #2 for the first time I did not have to do a manual driver install and it showed up as COM 11 (Arduino Mega). Today I thought I would try and determine what the problem was with Mega #1. So I plugged it in with the Ethernet shield and had trouble getting the IDE to recognise it. Eventually it showed up as COM 9 (Arduino Uno). I deleted/reinstalled/updated/rebooted etc etc but it always reverts to COM 9 (Arduino Uno).
I was able to upload to it with board selceted as Mega but port selected as COM 9 (Arduino Uno) and in fact the LAN connection is now also working!
My concern is I believe the compiler uses the IDE settings when compiling. So I am wondering if I will have compile issues due the port?
Anybody else experienced something similar to this?