diff --git a/src/drivers/device/spi.cpp b/src/drivers/device/spi.cpp
index fed6c312c1..0b232e158a 100644
--- a/src/drivers/device/spi.cpp
+++ b/src/drivers/device/spi.cpp
@@ -69,11 +69,11 @@ SPI::SPI(const char *name,
 	// protected
 	locking_mode(LOCK_PREEMPTION),
 	// private
-	_bus(bus),
 	_device(device),
 	_mode(mode),
 	_frequency(frequency),
-	_dev(nullptr)
+	_dev(nullptr),
+	_bus(bus)
 {
 }
 
diff --git a/src/drivers/hmc5883/hmc5883.cpp b/src/drivers/hmc5883/hmc5883.cpp
index 72d6bdd959..c2e4700d83 100644
--- a/src/drivers/hmc5883/hmc5883.cpp
+++ b/src/drivers/hmc5883/hmc5883.cpp
@@ -1266,7 +1266,7 @@ int	calibrate(int bus);
  * Start the driver.
  */
 void
-start(enum Rotation rotation)
+start(int bus, enum Rotation rotation)
 {
 	int fd;
 
@@ -1528,6 +1528,7 @@ int
 hmc5883_main(int argc, char *argv[])
 {
 	int ch;
+	int bus = -1;
 	enum Rotation rotation = ROTATION_NONE;
         bool calibrate = false;