diff --git a/serial_darwin.go b/serial_darwin.go
index 7bce6c9..8b27a82 100644
--- a/serial_darwin.go
+++ b/serial_darwin.go
@@ -14,3 +14,18 @@ const regexFilter = "^(cu|tty)\\..*"
 const ioctlTcgetattr = unix.TIOCGETA
 const ioctlTcsetattr = unix.TIOCSETA
 const ioctlTcflsh = unix.TIOCFLUSH
+
+func setTermSettingsBaudrate(speed int, settings *unix.Termios) (error, bool) {
+	baudrate, ok := baudrateMap[speed]
+	if !ok {
+		return nil, true
+	}
+	settings.Ispeed = toTermiosSpeedType(baudrate)
+	settings.Ospeed = toTermiosSpeedType(baudrate)
+	return nil, false
+}
+
+func (port *unixPort) setSpecialBaudrate(speed uint32) error {
+	const kIOSSIOSPEED = 0x80045402
+	return unix.IoctlSetPointerInt(port.handle, kIOSSIOSPEED, int(speed))
+}
diff --git a/serial_freebsd.go b/serial_freebsd.go
index a56a4bf..b648b52 100644
--- a/serial_freebsd.go
+++ b/serial_freebsd.go
@@ -60,3 +60,26 @@ const ioctlTcflsh = unix.TIOCFLUSH
 func toTermiosSpeedType(speed uint32) uint32 {
 	return speed
 }
+
+func setTermSettingsBaudrate(speed int, settings *unix.Termios) (error, bool) {
+	baudrate, ok := baudrateMap[speed]
+	if !ok {
+		return nil, true
+	}
+	// XXX: Is Cflag really needed
+	// revert old baudrate
+	for _, rate := range baudrateMap {
+		settings.Cflag &^= rate
+	}
+	// set new baudrate
+	settings.Cflag |= baudrate
+
+	settings.Ispeed = toTermiosSpeedType(baudrate)
+	settings.Ospeed = toTermiosSpeedType(baudrate)
+	return nil, false
+}
+
+func (port *unixPort) setSpecialBaudrate(speed uint32) error {
+	// TODO: unimplemented
+	return &PortError{code: InvalidSpeed}
+}
diff --git a/serial_linux.go b/serial_linux.go
index 1c8fd8d..eab3803 100644
--- a/serial_linux.go
+++ b/serial_linux.go
@@ -67,3 +67,31 @@ const ioctlTcflsh = unix.TCFLSH
 func toTermiosSpeedType(speed uint32) uint32 {
 	return speed
 }
+
+func setTermSettingsBaudrate(speed int, settings *unix.Termios) (error, bool) {
+	baudrate, ok := baudrateMap[speed]
+	if !ok {
+		return nil, true
+	}
+	// revert old baudrate
+	for _, rate := range baudrateMap {
+		settings.Cflag &^= rate
+	}
+	// set new baudrate
+	settings.Cflag |= baudrate
+	settings.Ispeed = toTermiosSpeedType(baudrate)
+	settings.Ospeed = toTermiosSpeedType(baudrate)
+	return nil, false
+}
+
+func (port *unixPort) setSpecialBaudrate(speed uint32) error {
+	settings, err := unix.IoctlGetTermios(port.handle, unix.TCGETS2)
+	if err != nil {
+		return err
+	}
+	settings.Cflag &^= unix.CBAUD
+	settings.Cflag |= unix.BOTHER
+	settings.Ispeed = speed
+	settings.Ospeed = speed
+	return unix.IoctlSetTermios(port.handle, unix.TCSETS2, settings)
+}
diff --git a/serial_openbsd.go b/serial_openbsd.go
index 5f626f3..ad68957 100644
--- a/serial_openbsd.go
+++ b/serial_openbsd.go
@@ -60,3 +60,26 @@ const ioctlTcflsh = unix.TIOCFLUSH
 func toTermiosSpeedType(speed uint32) int32 {
 	return int32(speed)
 }
+
+func setTermSettingsBaudrate(speed int, settings *unix.Termios) (error, bool) {
+	baudrate, ok := baudrateMap[speed]
+	if !ok {
+		return nil, true
+	}
+	// XXX: Is Cflag really needed
+	// revert old baudrate
+	for _, rate := range baudrateMap {
+		settings.Cflag &^= rate
+	}
+	// set new baudrate
+	settings.Cflag |= baudrate
+
+	settings.Ispeed = toTermiosSpeedType(baudrate)
+	settings.Ospeed = toTermiosSpeedType(baudrate)
+	return nil, false
+}
+
+func (port *unixPort) setSpecialBaudrate(speed uint32) error {
+	// TODO: unimplemented
+	return &PortError{code: InvalidSpeed}
+}
diff --git a/serial_unix.go b/serial_unix.go
index 0143aa2..143818e 100644
--- a/serial_unix.go
+++ b/serial_unix.go
@@ -126,9 +126,6 @@ func (port *unixPort) SetMode(mode *Mode) error {
 	if err != nil {
 		return err
 	}
-	if err := setTermSettingsBaudrate(mode.BaudRate, settings); err != nil {
-		return err
-	}
 	if err := setTermSettingsParity(mode.Parity, settings); err != nil {
 		return err
 	}
@@ -138,7 +135,23 @@ func (port *unixPort) SetMode(mode *Mode) error {
 	if err := setTermSettingsStopBits(mode.StopBits, settings); err != nil {
 		return err
 	}
-	return port.setTermSettings(settings)
+	requireSpecialBaudrate := false
+	if err, special := setTermSettingsBaudrate(mode.BaudRate, settings); err != nil {
+		return err
+	} else if special {
+		requireSpecialBaudrate = true
+	}
+	if err := port.setTermSettings(settings); err != nil {
+		return err
+	}
+	if requireSpecialBaudrate {
+		// MacOSX require this one to be the last operation otherwise an
+		// 'Invalid serial port' error is produced.
+		if err := port.setSpecialBaudrate(uint32(mode.BaudRate)); err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func (port *unixPort) SetDTR(dtr bool) error {
@@ -206,11 +219,6 @@ func nativeOpen(portName string, mode *Mode) (*unixPort, error) {
 	}
 
 	// Setup serial port
-	if port.SetMode(mode) != nil {
-		port.Close()
-		return nil, &PortError{code: InvalidSerialPort}
-	}
-
 	settings, err := port.getTermSettings()
 	if err != nil {
 		port.Close()
@@ -228,6 +236,13 @@ func nativeOpen(portName string, mode *Mode) (*unixPort, error) {
 		return nil, &PortError{code: InvalidSerialPort}
 	}
 
+	// MacOSX require that this operation is the last one otherwise an
+	// 'Invalid serial port' error is returned... don't know why...
+	if port.SetMode(mode) != nil {
+		port.Close()
+		return nil, &PortError{code: InvalidSerialPort}
+	}
+
 	unix.SetNonblock(h, false)
 
 	port.acquireExclusiveAccess()
@@ -289,22 +304,6 @@ func nativeGetPortsList() ([]string, error) {
 
 // termios manipulation functions
 
-func setTermSettingsBaudrate(speed int, settings *unix.Termios) error {
-	baudrate, ok := baudrateMap[speed]
-	if !ok {
-		return &PortError{code: InvalidSpeed}
-	}
-	// revert old baudrate
-	for _, rate := range baudrateMap {
-		settings.Cflag &^= rate
-	}
-	// set new baudrate
-	settings.Cflag |= baudrate
-	settings.Ispeed = toTermiosSpeedType(baudrate)
-	settings.Ospeed = toTermiosSpeedType(baudrate)
-	return nil
-}
-
 func setTermSettingsParity(parity Parity, settings *unix.Termios) error {
 	switch parity {
 	case NoParity: