diff --git a/cmd/importcombinedjson.go b/cmd/importcombinedjson.go
index 08b6b48..afd2bc9 100644
--- a/cmd/importcombinedjson.go
+++ b/cmd/importcombinedjson.go
@@ -44,7 +44,7 @@ type CombinedJSON struct {
 	RollupGasTokenAddress      common.Address `json:"gasTokenAddress"`
 	DACAddress                 common.Address `json:"polygonDataCommitteeAddress"`
 	BatchL2Data                string         `json:"batchL2Data,omitempty"`
-	LastGlobalExitRoot         common.Hash    `json:"globalExitRoot,omitempty"`
+	RollupGlobalExitRoot       common.Hash    `json:"globalExitRoot,omitempty"`
 }
 
 func importCombinedJson(cliCtx *cli.Context) error {
@@ -77,9 +77,9 @@ func importCombinedJson(cliCtx *cli.Context) error {
 	}
 
 	var (
-		dacAddr            common.Address
-		batchL2Data        string
-		lastGlobalExitRoot common.Hash
+		dacAddr              common.Address
+		batchL2Data          string
+		rollupGlobalExitRoot common.Hash
 	)
 
 	switch rollupMetadata.VerifierType {
@@ -94,7 +94,7 @@ func importCombinedJson(cliCtx *cli.Context) error {
 			return fmt.Errorf("failed to retrieve batch l2 data %w", err)
 		}
 
-		lastGlobalExitRoot, err = r.GetLastGlobalExitRoot(rollupManager, client)
+		rollupGlobalExitRoot, err = r.GetRollupGlobalExitRoot(rollupManager, client)
 		if err != nil {
 			return fmt.Errorf("failed to retrieve batch l2 data %w", err)
 		}
@@ -128,7 +128,7 @@ func importCombinedJson(cliCtx *cli.Context) error {
 		RollupGasTokenAddress:      rollupMetadata.GasToken,
 		DACAddress:                 dacAddr,
 		BatchL2Data:                batchL2Data,
-		LastGlobalExitRoot:         lastGlobalExitRoot,
+		RollupGlobalExitRoot:       rollupGlobalExitRoot,
 	}
 
 	raw, err := json.MarshalIndent(combinedJson, "", "   ")
diff --git a/rollup/rollup_pessimistic_proofs.go b/rollup/rollup_pessimistic_proofs.go
index a8f44a9..71ea0d3 100644
--- a/rollup/rollup_pessimistic_proofs.go
+++ b/rollup/rollup_pessimistic_proofs.go
@@ -116,8 +116,8 @@ func (r *RollupPessimisticProofs) GetBatchL2Data(client bind.ContractBackend) (s
 	return hexutil.Encode(rawTxWithSignature), nil
 }
 
-// GetLastGlobalExitRoot retrieves the last global exit root from global exit root manager
-func (r *RollupPessimisticProofs) GetLastGlobalExitRoot(rm *rollupmanager.RollupManager, client bind.ContractBackend) (common.Hash, error) {
+// GetRollupGlobalExitRoot retrieves the actual global exit root at the rollup creation time
+func (r *RollupPessimisticProofs) GetRollupGlobalExitRoot(rm *rollupmanager.RollupManager, client bind.ContractBackend) (common.Hash, error) {
 	gerContract, err := polygonzkevmglobalexitrootv2.NewPolygonzkevmglobalexitrootv2(rm.GERAddr, client)
 	if err != nil {
 		return common.Hash{}, err
@@ -128,12 +128,17 @@ func (r *RollupPessimisticProofs) GetLastGlobalExitRoot(rm *rollupmanager.Rollup
 	}
 
 	endBlock := r.CreationBlock - 1
-	iter, err := gerContract.FilterUpdateL1InfoTree(
-		&bind.FilterOpts{
-			Start: rm.UpdateToULxLyBlock,
-			End:   &endBlock,
-		}, nil, nil)
 
+	if endBlock < rm.UpdateToULxLyBlock {
+		return common.Hash{}, fmt.Errorf("end block (%d) is less than starting block (%d) in UpdateL1InfoTree filter",
+			rm.UpdateToULxLyBlock, endBlock)
+	}
+
+	filter := &bind.FilterOpts{
+		Start: rm.UpdateToULxLyBlock,
+		End:   &endBlock,
+	}
+	iter, err := gerContract.FilterUpdateL1InfoTree(filter, nil, nil)
 	if err != nil {
 		return common.Hash{}, err
 	}