I give up. I've removed the Revo from the Quad, and followed all the steps in the link above. I do not even get the I2C port being recognized now. I've got it powered up externally, using a UBEC, and am plugging that in first powering up Sparky2, and then the USB. It gets 15 Sats, but still no luck at all with the compass. (No I2C) I complained to Banggood about this. Possibly they will get back to me with a fix (or replacement). Can anyone suggest another GPS/Compass that I may try?