The I2C on my Bosch BMP280 quit working so I switched to SPI. I could read cal registers but I could not write to control and config registers. Dummy me, it took more than a few minutes to figure this one out.
So be aware that these two writeable registers have advertised address of 0xF4 and 0xF5 in the register table. The MSB clobbers R/W making it always read. The registers are defined in Chapter 4 of the datasheet but the need to lop off the MSB is in the SPI description in chapter 5. Duh me!
So be forewarned.