diff --git a/main/load-tx-rlp.zkasm b/main/load-tx-rlp.zkasm
index 1a34172b..a7056bd7 100644
--- a/main/load-tx-rlp.zkasm
+++ b/main/load-tx-rlp.zkasm
@@ -52,7 +52,7 @@ endList:
                                         :CALL(divARITH)
         $ => B                          :MLOAD(arithRes1)
         $ => D                          :MLOAD(cntKeccakPreProcess)
-        %MAX_CNT_KECCAK_F - CNT_KECCAK_F - B - D - 1:JMPN(outOfCountersKeccak)
+        %MAX_CNT_KECCAK_F - CNT_KECCAK_F - B - D - 1:JMPN(handleOOCatRLP)
 
 ;; Read RLP 'nonce'
         ; 64 bits max
@@ -322,18 +322,17 @@ vREADTx:
 ;; increase number of transaction to process
         $ => A                          :MLOAD(pendingTxs)
         A + 1 => A                      :MSTORE(pendingTxs)
-;; check signature
+;; compute signature
         $ => A                          :HASHKDIGEST(E)
-        $ => B                          :MLOAD(txR)
-        $ => C                          :MLOAD(txS)
-        $ => D                          :MLOAD(txV)
-                                        :CALL(ecrecover)
-        A                               :MSTORE(txSrcAddr)        
+        A                               :MSTORE(txHash)        
                                         :JMP(txLoopRLP)
 
 ;;;;;;;;;
 ;; E - Handler error RLP fields
 ;;;;;;;;;
+handleOOCatRLP:
+        ${eventLog(onError, OOCK)}
+        $ => SR         :MLOAD(batchSR)
 
 invalidTxRLP:
 ;; Append all missing 'batchL2Data' to 'batchDataHash' bytes
diff --git a/main/process-tx.zkasm b/main/process-tx.zkasm
index ffb45e29..373f8022 100644
--- a/main/process-tx.zkasm
+++ b/main/process-tx.zkasm
@@ -32,9 +32,16 @@ processTx:
 
         ; Minimum of 100000 steps left to process a tx
         %MAX_CNT_STEPS - STEP - 100000 :JMPN(outOfCountersStep)
-        ; check from address
+        $ => A                          :MLOAD(txHash)
+        ; Check the signature
+        $ => B                          :MLOAD(txR)
+        $ => C                          :MLOAD(txS)
+        $ => D                          :MLOAD(txV)
+                                        :CALL(ecrecover)
+        ; Check result is non-zero
+checkAndSaveFrom:
         0 => B
-        $ => A                          :MLOAD(txSrcAddr)
+        A                               :MSTORE(txSrcAddr)
         A                               :MSTORE(txSrcOriginAddr)
         $                               :EQ,JMPC(invalidIntrinsicTxSignature)
 
diff --git a/main/vars.zkasm b/main/vars.zkasm
index b3b78dee..919e8a24 100644
--- a/main/vars.zkasm
+++ b/main/vars.zkasm
@@ -60,6 +60,7 @@ VAR CTX txS ; transaction parameter: ecdsa signature S
 VAR CTX txR ; transaction parameter: ecdsa signature R
 VAR CTX txV ; transaction parameter: ecdsa signature V
 VAR CTX txSrcAddr ; address that sends a transaction 'message.sender'
+VAR CTX txHash ; signed tx hash
 VAR CTX txCalldataLen ; calldata length
 VAR CTX isCreateContract ; flag to determine if a transaction will create a new contract
 VAR CTX createContractAddress ; address computed of a new contract