diff --git a/mutants/mutant-1/swen90006/machine/Machine.java b/mutants/mutant-1/swen90006/machine/Machine.java
index 9bf57316d1c736ea2bd1c62bd6df3c6c0282f331..2c2c13c0855d6c8212198d4085c069064fe83f8a 100644
--- a/mutants/mutant-1/swen90006/machine/Machine.java
+++ b/mutants/mutant-1/swen90006/machine/Machine.java
@@ -148,7 +148,7 @@ public class Machine
   private void validate_offset(int offset)
     throws InvalidInstructionException
   {
-    if (offset < -MAX_ADDR || offset > MAX_ADDR) {
+    if (offset < -MAX_ADDR || offset > MAX_ADDR+1) {
       throw new InvalidInstructionException();
     }
   }