diff --git a/halo2_proofs/src/plonk.rs b/halo2_proofs/src/plonk.rs
index 85a544d585..9c1bc6eaa6 100644
--- a/halo2_proofs/src/plonk.rs
+++ b/halo2_proofs/src/plonk.rs
@@ -108,7 +108,8 @@ pub struct VerifyingKey<C: CurveAffine> {
     domain: EvaluationDomain<C::Scalar>,
     fixed_commitments: Vec<C>,
     permutation: permutation::VerifyingKey<C>,
-    cs: ConstraintSystem<C::Scalar>,
+    /// TODO: Remove pub
+    pub cs: ConstraintSystem<C::Scalar>,
     /// Cached maximum degree of `cs` (which doesn't change after construction).
     cs_degree: usize,
     /// The representative of this `VerifyingKey` in transcripts.
diff --git a/halo2_proofs/src/plonk/keygen.rs b/halo2_proofs/src/plonk/keygen.rs
index 6014ac55d8..eb47d26887 100644
--- a/halo2_proofs/src/plonk/keygen.rs
+++ b/halo2_proofs/src/plonk/keygen.rs
@@ -275,7 +275,9 @@ where
     C::Scalar: FromUniformBytes<64>,
 {
     let (compiled_circuit, _, _) = compile_circuit(params.k(), circuit, compress_selectors)?;
-    keygen_vk_v2(params, &compiled_circuit)
+    let mut vk = keygen_vk_v2(params, &compiled_circuit)?;
+    vk.compress_selectors = compress_selectors;
+    Ok(vk)
 }
 
 // TODO: Remove
diff --git a/halo2_proofs/src/plonk/prover.rs b/halo2_proofs/src/plonk/prover.rs
index e694e4427f..62f45e85c3 100644
--- a/halo2_proofs/src/plonk/prover.rs
+++ b/halo2_proofs/src/plonk/prover.rs
@@ -283,6 +283,8 @@ impl<
         let params = self.params;
         let meta = &self.pk.vk.cs;
         // let queries = &self.pk.vk.queries;
+        // println!("DBG commit_phase gate {:?}", meta.gates()[0]);
+        // println!("DBG commit_phase queries {:?}", meta.advice_queries());
 
         let mut rng = &mut self.rng;
 
@@ -888,7 +890,7 @@ pub fn create_proof_legacy<
     pk: &ProvingKey<Scheme::Curve>,
     circuits: &[ConcreteCircuit],
     instances: &[&[&[Scheme::Scalar]]],
-    mut rng: R,
+    rng: R,
     transcript: &mut T,
 ) -> Result<(), Error>
 where
diff --git a/halo2_proofs/tests/frontend_backend_split.rs b/halo2_proofs/tests/frontend_backend_split.rs
index 7f6558bf49..34a71ff59b 100644
--- a/halo2_proofs/tests/frontend_backend_split.rs
+++ b/halo2_proofs/tests/frontend_backend_split.rs
@@ -11,11 +11,10 @@ use halo2_proofs::arithmetic::Field;
 use halo2_proofs::circuit::{AssignedCell, Cell, Layouter, Region, SimpleFloorPlanner, Value};
 use halo2_proofs::dev::MockProver;
 use halo2_proofs::plonk::{
-    compile_circuit, create_proof, keygen_pk, keygen_pk_v2, keygen_vk, keygen_vk_v2, verify_proof,
-    verify_proof_single, Advice, Assigned, Challenge, Circuit, Column, CompiledCircuitV2,
-    ConstraintSystem, ConstraintSystemV2Backend, Error, Expression, FirstPhase, Fixed, Instance,
-    ProverV2Single, ProvingKey, SecondPhase, Selector, TableColumn, VerifyingKey,
-    WitnessCalculator,
+    compile_circuit, keygen_pk_v2, keygen_vk_v2, verify_proof, verify_proof_single, Advice,
+    Assigned, Challenge, Circuit, Column, CompiledCircuitV2, ConstraintSystem,
+    ConstraintSystemV2Backend, Error, Expression, FirstPhase, Fixed, Instance, ProverV2Single,
+    ProvingKey, SecondPhase, Selector, TableColumn, VerifyingKey, WitnessCalculator,
 };
 use halo2_proofs::poly::commitment::{CommitmentScheme, ParamsProver, Prover, Verifier};
 use halo2_proofs::poly::Rotation;
@@ -161,9 +160,9 @@ impl<F: Field + From<u64>, const WIDTH_FACTOR: usize> MyCircuit<F, WIDTH_FACTOR>
 
         meta.create_gate("gate_a", |meta| {
             let s_gate = meta.query_selector(s_gate);
+            let b = meta.query_advice(b, Rotation::cur());
             let a1 = meta.query_advice(a, Rotation::next());
             let a0 = meta.query_advice(a, Rotation::cur());
-            let b = meta.query_advice(b, Rotation::cur());
             let c = meta.query_advice(c, Rotation::cur());
             let d = meta.query_fixed(d, Rotation::cur());
 
@@ -488,6 +487,7 @@ fn test_mycircuit_full_legacy() {
         create_proof_legacy as create_proof, keygen_pk_legacy as keygen_pk,
         keygen_vk_legacy as keygen_vk,
     };
+    // use halo2_proofs::plonk::{create_proof, keygen_pk, keygen_vk};
 
     let k = K;
     let circuit: MyCircuit<Fr, WIDTH_FACTOR> = MyCircuit::new(k, 42);
@@ -498,6 +498,8 @@ fn test_mycircuit_full_legacy() {
     let verifier_params = params.verifier_params();
     let start = Instant::now();
     let vk = keygen_vk(&params, &circuit).expect("keygen_vk should not fail");
+    // println!("DBG gate {:?}", vk.cs.gates()[0]);
+    // println!("DBG queries {:?}", vk.cs.advice_queries());
     let pk = keygen_pk(&params, vk.clone(), &circuit).expect("keygen_pk should not fail");
     println!("Keygen: {:?}", start.elapsed());
 
diff --git a/rust-toolchain b/rust-toolchain
index b6148bc0a7..7c7053aa23 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-1.66.0
+1.75.0
diff --git a/scratch b/scratch
new file mode 100644
index 0000000000..ab22c18135
--- /dev/null
+++ b/scratch
@@ -0,0 +1,137 @@
+DBG collected queries
+Queries {
+    advice: [
+        (
+            Column {
+                index: 0,
+                column_type: Advice,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+        (
+            Column {
+                index: 0,
+                column_type: Advice,
+            },
+            Rotation(
+                1,
+            ),
+        ),
+        (
+            Column {
+                index: 1,
+                column_type: Advice,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+        (
+            Column {
+                index: 2,
+                column_type: Advice,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+    ],
+    instance: [],
+    fixed: [
+        (
+            Column {
+                index: 0,
+                column_type: Fixed,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+        (
+            Column {
+                index: 5,
+                column_type: Fixed,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+    ],
+    num_advice_queries: [
+        2,
+        1,
+        1,
+        0,
+    ],
+}
+DBG collected queries
+Queries {
+    advice: [
+        (
+            Column {
+                index: 0,
+                column_type: Advice,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+        (
+            Column {
+                index: 0,
+                column_type: Advice,
+            },
+            Rotation(
+                1,
+            ),
+        ),
+        (
+            Column {
+                index: 1,
+                column_type: Advice,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+        (
+            Column {
+                index: 2,
+                column_type: Advice,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+    ],
+    instance: [],
+    fixed: [
+        (
+            Column {
+                index: 0,
+                column_type: Fixed,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+        ( # EXTRA
+            Column {
+                index: 5,
+                column_type: Fixed,
+            },
+            Rotation(
+                0,
+            ),
+        ),
+    ],
+    num_advice_queries: [
+        2,
+        1,
+        1,
+        0,
+    ],
+}
+