diff --git a/fuzzer/Fuzzer.java b/fuzzer/Fuzzer.java
index 039f23968fcb077c634e01a6a7b85aac2b97127f..2c3863a4847e6457cbc17d5428fd54ad5b697e70 100644
--- a/fuzzer/Fuzzer.java
+++ b/fuzzer/Fuzzer.java
@@ -32,7 +32,7 @@ public class Fuzzer {
             };
             pw.println("RET R31");*/
             //pw.println("JZ R0 -2"); 
-            pw.println("RET R0");
+            pw.println("RET R31");
  
         }catch (Exception e){
             e.printStackTrace(System.err);
diff --git a/src/machine-vuln4.c b/src/machine-vuln4.c
index 46b0e2e9bd7ccfe162e8f8df63499a5938fe478e..7ade421004ab3f45b0fdb2f71d70a0ce3ca72751 100644
--- a/src/machine-vuln4.c
+++ b/src/machine-vuln4.c
@@ -57,8 +57,8 @@ unsigned int count = 0; /* counts number of instructions executed so far */
 static void machine_init(void){
   memory = malloc(sizeof(int32_t)*MEMORY_SIZE);
   regs = malloc(sizeof(int32_t)*NUM_REGS);
-  //Zmemset(memory,0,sizeof(int32_t)*MEMORY_SIZE);
-  //memset(regs,0,sizeof(int32_t)*NUM_REGS);
+  memset(memory,0,sizeof(int32_t)*MEMORY_SIZE);
+  memset(regs,0,sizeof(int32_t)*(NUM_REGS-1));
   count = 0;
 }