cd /boot/uboot/dtbs/
dtc -I dtb -O dts am335x-boneblack.dtb > am335x-boneblack.dts
vi am335x-boneblack.dts
sarch for

/*
                pinmux_i2c2_pins {
                        pinctrl-single,pins = <0x178 0x73 0x17c 0x73>;
                        linux,phandle = <0x7>;
                        phandle = <0x7>;
                };
*/


/*
                i2c2 = "/ocp/i2c@4819c000";
*/


dtc -O dtb -o am335x-boneblack.dtb -b 0 am335x-boneblack.dts