diff --git a/src/codegen.rs b/src/codegen.rs
index c359958..547a90a 100644
--- a/src/codegen.rs
+++ b/src/codegen.rs
@@ -97,9 +97,8 @@ impl<'a> SolidityGenerator<'a> {
         num_instances: usize,
     ) -> Self {
         assert_ne!(vk.cs().num_advice_columns(), 0);
-        assert_eq!(
-            vk.cs().num_instance_columns(),
-            1,
+        assert!(
+            vk.cs().num_instance_columns() <= 1,
             "Multiple instance columns is not yet implemented"
         );
         assert!(
diff --git a/templates/Halo2Verifier.sol b/templates/Halo2Verifier.sol
index bd917bb..81b2db6 100644
--- a/templates/Halo2Verifier.sol
+++ b/templates/Halo2Verifier.sol
@@ -380,6 +380,9 @@ contract Halo2Verifier {
 
                 let mptr := X_N_MPTR
                 let mptr_end := add(mptr, mul(0x20, add(mload(NUM_INSTANCES_MPTR), {{ num_neg_lagranges }})))
+                if iszero(mload(NUM_INSTANCES_MPTR)) {
+                    mptr_end := add(mptr_end, 0x20)
+                }
                 for
                     { let pow_of_omega := mload(OMEGA_INV_TO_L_MPTR) }
                     lt(mptr, mptr_end)
@@ -413,11 +416,12 @@ contract Halo2Verifier {
                     l_blind := addmod(l_blind, mload(l_i_cptr), r)
                 }
 
-                let instance_eval := mulmod(mload(l_i_cptr), calldataload(INSTANCE_CPTR), r)
-                let instance_cptr := add(INSTANCE_CPTR, 0x20)
-                l_i_cptr := add(l_i_cptr, 0x20)
+                let instance_eval := 0
                 for
-                    { let instance_cptr_end := add(INSTANCE_CPTR, mul(0x20, mload(NUM_INSTANCES_MPTR))) }
+                    {
+                        let instance_cptr := INSTANCE_CPTR
+                        let instance_cptr_end := add(instance_cptr, mul(0x20, mload(NUM_INSTANCES_MPTR)))
+                    }
                     lt(instance_cptr, instance_cptr_end)
                     {
                         instance_cptr := add(instance_cptr, 0x20)