diff --git a/tools/i2cdetect.c b/tools/i2cdetect.c
index f2552f1..33f01a8 100644
--- a/tools/i2cdetect.c
+++ b/tools/i2cdetect.c
@@ -228,8 +228,8 @@ int main(int argc, char *argv[])
 			last = 0x7F;
 			break;
 		default:
-			fprintf(stderr, "Warning: Unsupported flag "
-				"\"-%c\"!\n", argv[1+flags][1]);
+			fprintf(stderr, "Error: Unsupported option "
+				"\"%s\"!\n", argv[1+flags]);
 			help();
 			exit(1);
 		}
diff --git a/tools/i2cdump.c b/tools/i2cdump.c
index bad8ccf..c4de81b 100644
--- a/tools/i2cdump.c
+++ b/tools/i2cdump.c
@@ -68,8 +68,8 @@ int main(int argc, char *argv[])
 		case 'r': range = argv[1+(++flags)]; break;
 		case 'y': yes = 1; break;
 		default:
-			fprintf(stderr, "Warning: Unsupported flag "
-				"\"-%c\"!\n", argv[1+flags][1]);
+			fprintf(stderr, "Error: Unsupported option "
+				"\"%s\"!\n", argv[1+flags]);
 			help();
 			exit(1);
 		}
diff --git a/tools/i2cget.c b/tools/i2cget.c
index 747a6a9..ae7a8f5 100644
--- a/tools/i2cget.c
+++ b/tools/i2cget.c
@@ -169,8 +169,8 @@ int main(int argc, char *argv[])
 		case 'f': force = 1; break;
 		case 'y': yes = 1; break;
 		default:
-			fprintf(stderr, "Warning: Unsupported flag "
-				"\"-%c\"!\n", argv[1+flags][1]);
+			fprintf(stderr, "Error: Unsupported option "
+				"\"%s\"!\n", argv[1+flags]);
 			help();
 			exit(1);
 		}
diff --git a/tools/i2cset.c b/tools/i2cset.c
index 88a62c6..5e14bcd 100644
--- a/tools/i2cset.c
+++ b/tools/i2cset.c
@@ -63,8 +63,8 @@ int main(int argc, char *argv[])
 		case 'f': force = 1; break;
 		case 'y': yes = 1; break;
 		default:
-			fprintf(stderr, "Warning: Unsupported flag "
-				"\"-%c\"!\n", argv[1+flags][1]);
+			fprintf(stderr, "Error: Unsupported option "
+				"\"%s\"!\n", argv[1+flags]);
 			help();
 			exit(1);
 		}