diff --git a/README.md b/README.md
index bf3e254..8ca41e8 100644
--- a/README.md
+++ b/README.md
@@ -32,12 +32,12 @@ Consider yourself forewarned, and forearmed.
 $ ./cp210x-cfg -h
 Syntax:
 cp210x-cfg [-h ] |
-           [-m vid:pid] [-d bus:dev]
+           [-m vid:pid] [-d bus.dev]
            [ -l | [-V vid] [-P pid] [-F flush] [-M mode] [-N name] [-S serial]]
 
   -h            This help
   -m vid:pid    Find and use first device with vid:pid
-  -d bus:dev    Find and use device at bus:dev
+  -d bus.dev    Find and use device at bus.dev
   -l            List all CP210x devices connected
   -V vid        Program the given Vendor ID
   -P pid        Program the given Product ID
diff --git a/src/main.c b/src/main.c
index d7598fc..18f203c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -283,12 +283,12 @@ void syntax (void)
   fprintf (stderr,
 "Syntax:\n"
 "cp210x-cfg [-h ] |\n"
-"           [-m vid:pid] [-d bus:dev]\n"
+"           [-m vid:pid] [-d bus.dev]\n"
 "           [ -l | [-V vid] [-P pid] [-F flush] [-M mode] [-N name] [-S serial]]\n" 
 "\n"
 "  -h            This help\n"
 "  -m vid:pid    Find and use first device with vid:pid\n"
-"  -d bus:dev    Find and use device at bus:dev\n"
+"  -d bus.dev    Find and use device at bus.dev\n"
 "  -l            List all CP210x devices connected\n"
 "  -V vid        Program the given Vendor ID\n"
 "  -P pid        Program the given Product ID\n"
@@ -351,7 +351,7 @@ int main (int argc, char *argv[])
           fprintf (stderr, "error: bad format to -d option, expected n.n\n");
           return 10;
         }
-        want_dev = strtol (++p, NULL, 0);
+        want_dev = strtol (++p, NULL, 10);
         break;
       }
       case 'm':