Hi hockeyplaya23,
Typically, BNO055 is the part number for customers that wish to use the Bosch Sensortec firmware, and BMF055 is the part number for customer that wish to program the device on their own.
Nevertheless both parts are identical and you can use an SWD programmer to erase the built-in firmware on your BNO055 and flash your own. Please refer to the BMF055 datasheet in this case on how to program the SAMD20J18 RevB microcontroller inside.