I personally have had trouble getting an I2C device to work with Galileo.
I have gotten my serial LCD to work by adding just one line of code in the Setup function.
lcd.init(1,12,255,11,5,4,3,2,0,0,0,0); //Place before any lcd access.
the lcd.init() is a fix for parallel LCD. I2C LCD still does not work.
This example works well with the Sparkfun 16x2 Serial (3 wire TX/RX/GND) Display. The biggest tricks are:
1: knowing to connect TX to RX from the Controller CCA to the display. (some equipment does not follow that standard)
2: The device suggested it works by default at 9600 BPS, I found using 19200BPS to work nicely.
3: finding out that the MicroControllers ports for TX and RX are not called Serial in the library, but are instead called Serial1.