Add problem with multiple SPI module on the same port (MPU9250 and SD card reader, also 2 oled) Oleds worked because they do not need MISO to work. When I both use SD and MPU, I lost mpu data but the logs are written on the sd card, this happen also without sd card in the module. I read that it is because the MISO line is still used even with the cs high and the best way to go around is to use buffer to cut miso from the bus when cs is high. My sd module come with a LVC125 chip (U1). This chip is a buffer gate but all CS,MISO, MOSI and SCK output enable (OE) pin are tied on GND, that means it does not cut the signal. I didn't want to add an external buffer and I cut the miso OE pin from ground and connect it to CS (green wire), it was kind of difficult because the GND track was under the chip. One dirty/faster way would be to de solder only this pin, remove the pad, solder the pin to the CS pin and secure it with glue. Since that both MPU and card reader work on the same SPI bus.