diff --git a/src/machine/i2c.go b/src/machine/i2c.go
index 384d3deed0..434b91ee35 100644
--- a/src/machine/i2c.go
+++ b/src/machine/i2c.go
@@ -36,6 +36,7 @@ var (
 	errI2CBusError           = errors.New("I2C bus error")
 	errI2COverflow           = errors.New("I2C receive buffer overflow")
 	errI2COverread           = errors.New("I2C transmit buffer overflow")
+	errI2CNotImplemented     = errors.New("I2C operation not yet implemented")
 )
 
 // I2CTargetEvent reflects events on the I2C bus
diff --git a/src/machine/machine_mimxrt1062_i2c.go b/src/machine/machine_mimxrt1062_i2c.go
index 8531eba1db..ee46ff9569 100644
--- a/src/machine/machine_mimxrt1062_i2c.go
+++ b/src/machine/machine_mimxrt1062_i2c.go
@@ -174,7 +174,7 @@ func (i2c *I2C) Configure(config I2CConfig) {
 // SetBaudRate sets the communication speed for I2C.
 func (i2c I2C) SetBaudRate(br uint32) error {
 	// TODO: implement
-	return nil
+	return errI2CNotImplemented
 }
 
 func (i2c I2C) Tx(addr uint16, w, r []byte) error {
diff --git a/src/machine/machine_stm32_i2c_reva.go b/src/machine/machine_stm32_i2c_reva.go
index 0dea71639b..1e4fd282e9 100644
--- a/src/machine/machine_stm32_i2c_reva.go
+++ b/src/machine/machine_stm32_i2c_reva.go
@@ -160,7 +160,7 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 // SetBaudRate sets the communication speed for I2C.
 func (i2c *I2C) SetBaudRate(br uint32) error {
 	// TODO: implement
-	return nil
+	return errI2CNotImplemented
 }
 
 func (i2c *I2C) Tx(addr uint16, w, r []byte) error {
diff --git a/src/machine/machine_stm32_i2c_revb.go b/src/machine/machine_stm32_i2c_revb.go
index 24ba8aec9d..9253902940 100644
--- a/src/machine/machine_stm32_i2c_revb.go
+++ b/src/machine/machine_stm32_i2c_revb.go
@@ -87,7 +87,7 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 // SetBaudRate sets the communication speed for I2C.
 func (i2c *I2C) SetBaudRate(br uint32) error {
 	// TODO: implement
-	return nil
+	return errI2CNotImplemented
 }
 
 func (i2c *I2C) Tx(addr uint16, w, r []byte) error {