diff --git a/tests/gadget-zero/README.md b/tests/gadget-zero/README.md
index 8586de10..b22cc627 100644
--- a/tests/gadget-zero/README.md
+++ b/tests/gadget-zero/README.md
@@ -27,9 +27,11 @@ broken, and are awaiting code fixes, or are long running performance tests
 
 ## Running the tests
 Below is an example of running the full suite of tests from the command line.
-The argument specifies the serial number to look for in the usb gadget.
+The argument specifies the serial number to look for in the usb gadget, if
+you have more than one.  No argument will the tests against all
+gadget-zero's found.
 ```
-$ python test_gadget0.py stm32f072disco
+$ python test_gadget0.py
 Running tests for DUT:  stm32f072disco
 .........ss................
 ----------------------------------------------------------------------
diff --git a/tests/gadget-zero/test_gadget0.py b/tests/gadget-zero/test_gadget0.py
index ec16f278..25e2fa2b 100644
--- a/tests/gadget-zero/test_gadget0.py
+++ b/tests/gadget-zero/test_gadget0.py
@@ -10,6 +10,8 @@ import unittest
 VENDOR_ID=0xcafe
 PRODUCT_ID=0xcafe
 
+# you only need to worry about these if you are trying to explicitly test
+# a single target.  Normally, the test will autofind the attached target
 #DUT_SERIAL = "stm32f429i-disco"
 DUT_SERIAL = "stm32f4disco"
 #DUT_SERIAL = "stm32f103-generic"
@@ -385,5 +387,12 @@ class TestUnaligned(unittest.TestCase):
 if __name__ == "__main__":
     if len(sys.argv) > 1:
         DUT_SERIAL = sys.argv.pop()
-    print("Running tests for DUT: ", DUT_SERIAL)
-    unittest.main()
+        print("Running tests for DUT: ", DUT_SERIAL)
+        unittest.main()
+    else:
+        # scan for available and try them all!
+        devs = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID, find_all=True)
+        for dev in devs:
+            DUT_SERIAL = dev.serial_number
+            print("Running tests for DUT: ", DUT_SERIAL)
+            unittest.main(exit=False)