These are the commands I entered to set up the I2C interface on my Edison + Mini Breakout board:
echo 28 > /sys/class/gpio/export echo 27 > /sys/class/gpio/export echo mode1 > /sys/kernel/debug/gpio_debug/gpio28/current_pinmux echo mode1 > /sys/kernel/debug/gpio_debug/gpio27/current_pinmux
If I try to run the "i2cdetect -r -y 6" command before I entered them I get a bunch of error messages but after everything seems to be working fine. Did you set up I2C this way? Does it make a difference?
I will give it a try and then get back to you...