diff --git a/crates/utils/src/helpers.cairo b/crates/utils/src/helpers.cairo
index 826ae240f..2eb94f6b2 100644
--- a/crates/utils/src/helpers.cairo
+++ b/crates/utils/src/helpers.cairo
@@ -528,42 +528,43 @@ impl U256Impl of U256Trait {
 #[generate_trait]
 impl ByteArrayExt of ByteArrayExTrait {
     fn from_bytes(mut bytes: Span<u8>) -> ByteArray {
-        //TODO(eni): optimize deserialization of Span<u8> to ByteArray;
-        // we can just deserialize bytes by chunks of 31, skipping pending_word
-        // checks
         let mut arr: ByteArray = Default::default();
-        let (mut q, mut r) = DivRem::div_rem(bytes.len(), 31_u32.try_into().unwrap());
+        let (mut nb_full_words, mut pending_word_len) = DivRem::div_rem(
+            bytes.len(), 31_u32.try_into().unwrap()
+        );
+        let mut i = 0;
         loop {
-            if q == 0 {
+            if i == nb_full_words {
                 break;
             };
             let mut word: felt252 = 0;
-            let mut i = 0;
+            let mut j = 0;
             loop {
-                if i == 31 {
+                if j == 31 {
                     break;
                 };
                 word = word * POW_256_1.into() + (*bytes.pop_front().unwrap()).into();
-                i += 1;
+                j += 1;
             };
-            arr.data.append(word.try_into().unwrap()); 
-            q -= 1;
+            arr.data.append(word.try_into().unwrap());
+            i += 1;
         };
 
-        if r == 0 {
+        if pending_word_len == 0 {
             return arr;
         };
 
-        arr.pending_word_len = r;
         let mut pending_word: felt252 = 0;
+        let mut i = 0;
 
         loop {
-            if r == 0 {
+            if i == pending_word_len {
                 break;
             };
             pending_word = pending_word * POW_256_1.into() + (*bytes.pop_front().unwrap()).into();
-            r -= 1;
+            i += 1;
         };
+        arr.pending_word_len = pending_word_len;
         arr.pending_word = pending_word;
         arr
     }