The I2C2 port and GPS2 I2C bus are the same I2C bus (The old internal I2C bus on Pixhawk 1)
The GPS1 I2C bus is the old external bus on Pixhawk 1.
I guess that the firmware still reads the SF11/c datas on the old external bus. That’s why it’s working on GPS1 port.
But I prefer to avoid cutting GPS cables, especially if there is an I2C port available on the board.
Right, so for many sensors we don’t have the ability to assign the I2C bus to use because on previous boards, only a single I2C bus was ever available to the user. There’s an existing similar similar to-do item so it’s on the list!