From b5ad2ac1c35be5a273f218355ee54f56fc4eca2f Mon Sep 17 00:00:00 2001
From: kunxian xia <xiakunxian130@gmail.com>
Date: Wed, 12 Jul 2023 12:45:55 +0800
Subject: [PATCH 1/2] fix finding 25

---
 zkevm-circuits/src/tx_circuit.rs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/zkevm-circuits/src/tx_circuit.rs b/zkevm-circuits/src/tx_circuit.rs
index a03b08c35c..9d0e4ef38e 100644
--- a/zkevm-circuits/src/tx_circuit.rs
+++ b/zkevm-circuits/src/tx_circuit.rs
@@ -99,6 +99,7 @@ pub struct TxCircuitConfig<F: Field> {
     tx_table: TxTable,
     tx_tag_bits: BinaryNumberConfig<TxFieldTag, 5>,
 
+    q_second: Column<Fixed>,
     tx_type: Column<Advice>,
     tx_type_bits: BinaryNumberConfig<TxType, 3>,
     // The associated rlp tag to lookup in the RLP table
@@ -186,6 +187,7 @@ impl<F: Field> SubCircuitConfig<F> for TxCircuitConfig<F> {
     ) -> Self {
         let q_enable = tx_table.q_enable;
 
+        let q_second = meta.fixed_column();
         // tag, rlp_tag, tx_type, is_none
         let tx_type = meta.advice_column();
         let rlp_tag = meta.advice_column();
@@ -294,6 +296,17 @@ impl<F: Field> SubCircuitConfig<F> for TxCircuitConfig<F> {
         );
 
         // tx_id transition
+        meta.create_gate("tx_id starts with 1", |meta| {
+            let mut cb = BaseConstraintBuilder::default();
+
+            cb.require_equal(
+                "tx_id == 1",
+                meta.query_advice(tx_table.tx_id, Rotation::cur()),
+                1.expr(),
+            );
+
+            cb.gate(meta.query_fixed(q_second, Rotation::cur()))
+        });
         meta.create_gate("tx_id transition", |meta| {
             let mut cb = BaseConstraintBuilder::default();
 
@@ -879,6 +892,7 @@ impl<F: Field> SubCircuitConfig<F> for TxCircuitConfig<F> {
             tx_type_bits,
             rlp_tag,
             is_none,
+            q_second,
             u16_table,
             tx_id_is_zero,
             value_is_zero,
@@ -1675,6 +1689,13 @@ impl<F: Field> TxCircuit<F> {
                     None,
                 )?;
 
+                region.assign_fixed(
+                    || "q_second",
+                    config.q_second,
+                    1,
+                    || Value::known(F::one()),
+                )?;
+
                 // Assign all tx fields except for call data
                 for (i, sign_data) in sigs.iter().enumerate() {
                     let tx = if i < self.txs.len() {

From 1b45784b0d78c97e6ff7febb4bbb4bbc6670a3af Mon Sep 17 00:00:00 2001
From: kunxian xia <xiakunxian130@gmail.com>
Date: Wed, 9 Aug 2023 17:43:08 +0800
Subject: [PATCH 2/2] add comment

---
 zkevm-circuits/src/tx_circuit.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/zkevm-circuits/src/tx_circuit.rs b/zkevm-circuits/src/tx_circuit.rs
index 6e3ad09584..eff086684a 100644
--- a/zkevm-circuits/src/tx_circuit.rs
+++ b/zkevm-circuits/src/tx_circuit.rs
@@ -101,6 +101,7 @@ pub struct TxCircuitConfig<F: Field> {
     tx_table: TxTable,
     tx_tag_bits: BinaryNumberConfig<TxFieldTag, 5>,
 
+    // A selector which is enabled at 2nd row
     q_second: Column<Fixed>,
     tx_type: Column<Advice>,
     tx_type_bits: BinaryNumberConfig<TxType, 3>,