Updated FAQ (markdown)

FAQ.md

@@ -210,4 +210,13 @@ avrdude -patmega32u4 -cavr109 -b57600 -Uflash:w:adb_usb.hex -P/dev/ttyACM0
 Device name will vary depending on your system.
 
 http://arduino.cc/en/Main/ArduinoBoardMicro
-https://geekhack.org/index.php?topic=14290.msg1563867#msg1563867
+https://geekhack.org/index.php?topic=14290.msg1563867#msg1563867
+
+
+## USB 3 compatibility
+I heard some people have a problem with USB 3 port, try USB 2 port.
+
+
+## Mac compatibility
+- OS X 10.11 and Hub: https://geekhack.org/index.php?topic=14290.msg1884034#msg1884034
+https://geekhack.org/index.php?topic=14290.msg1884034#msg1884034