diff --git a/fuzzers/FRET/src/systemstate/stg.rs b/fuzzers/FRET/src/systemstate/stg.rs
index ccd99db120..cb78e1b29c 100644
--- a/fuzzers/FRET/src/systemstate/stg.rs
+++ b/fuzzers/FRET/src/systemstate/stg.rs
@@ -12,6 +12,7 @@ use libafl::prelude::State;
 use libafl::schedulers::MinimizerScheduler;
 use libafl_bolts::HasRefCnt;
 use serde::de::DeserializeOwned;
+use std::cmp::min;
 use std::path::PathBuf;
 use std::sync::Arc;
 use libafl::corpus::Testcase;
@@ -381,7 +382,7 @@ where
 
 //============================= Graph Feedback
 
-pub const STG_MAP_SIZE: usize = 1<<28; // 512MB
+pub const STG_MAP_SIZE: usize = 1<<29; // 1024 MB
 pub static mut STG_MAP: [u16; STG_MAP_SIZE] = [0; STG_MAP_SIZE];
 pub static mut MAX_STG_NUM: usize = 0;
 pub unsafe fn stg_map_mut_slice<'a>() -> OwnedMutSlice<'a, u16> {
@@ -450,10 +451,10 @@ fn set_observer_map(trace : &Vec<EdgeIndex>) {
             STG_MAP[i] = 0;
         }
         for i in trace {
-            if MAX_STG_NUM < i.index() {
-                MAX_STG_NUM = i.index();
-            }
             if i.index() < STG_MAP.len() {
+                if MAX_STG_NUM < i.index() {
+                    MAX_STG_NUM = min(i.index(), STG_MAP.len() - 1);
+                }
                 STG_MAP[i.index()] = STG_MAP[i.index()].saturating_add(1);
             } else {
                 eprintln!("STG Map index out of bounds: {}", i.index());