diff --git a/devices/bmxx80/bmx280smoketest/bmx280smoketest.go b/devices/bmxx80/bmx280smoketest/bmx280smoketest.go
index f1769fb..eeeb253 100644
--- a/devices/bmxx80/bmx280smoketest/bmx280smoketest.go
+++ b/devices/bmxx80/bmx280smoketest/bmx280smoketest.go
@@ -8,6 +8,7 @@
 package bmx280smoketest
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 
@@ -37,12 +38,15 @@ func (s *SmokeTest) Description() string {
 
 // Run implements the SmokeTest interface.
 func (s *SmokeTest) Run(args []string) (err error) {
-	f := flag.NewFlagSet("buses", flag.ExitOnError)
+	f := flag.NewFlagSet(s.Name(), flag.ExitOnError)
 	i2cID := f.String("i2c", "", "I²C bus to use")
 	i2cAddr := f.Uint("ia", 0x76, "I²C bus address to use; either 0x76 (BMx280, the default) or 0x77 (BMP180)")
 	spiID := f.String("spi", "", "SPI port to use")
 	record := f.Bool("r", false, "record operation (for playback unit testing)")
 	f.Parse(args)
+	if f.NArg() != 0 {
+		return errors.New("unrecognized arguments")
+	}
 
 	i2cBus, err2 := i2creg.Open(*i2cID)
 	if err2 != nil {
diff --git a/devices/ssd1306/ssd1306smoketest/ssd1306smoketest.go b/devices/ssd1306/ssd1306smoketest/ssd1306smoketest.go
index 223e010..ba960d4 100644
--- a/devices/ssd1306/ssd1306smoketest/ssd1306smoketest.go
+++ b/devices/ssd1306/ssd1306smoketest/ssd1306smoketest.go
@@ -8,6 +8,7 @@ package ssd1306smoketest
 
 import (
 	"bytes"
+	"errors"
 	"flag"
 	"fmt"
 	"image"
@@ -53,7 +54,7 @@ func (s *SmokeTest) Description() string {
 func (s *SmokeTest) Run(args []string) (err error) {
 	s.delay = 2 * time.Second
 
-	f := flag.NewFlagSet("buses", flag.ExitOnError)
+	f := flag.NewFlagSet(s.Name(), flag.ExitOnError)
 	i2cID := f.String("i2c", "", "I²C bus to use")
 	spiID := f.String("spi", "", "SPI port to use")
 	dcName := f.String("dc", "", "DC pin to use in 4-wire SPI mode")
@@ -64,6 +65,9 @@ func (s *SmokeTest) Run(args []string) (err error) {
 
 	record := f.Bool("record", false, "record operation (for playback unit testing)")
 	f.Parse(args)
+	if f.NArg() != 0 {
+		return errors.New("unrecognized arguments")
+	}
 
 	i2cBus, err2 := i2creg.Open(*i2cID)
 	if err2 != nil {