diff --git a/contrib/test/test-vectors-commit-sha.txt b/contrib/test/test-vectors-commit-sha.txt
index c372c92256a..59bc5540e9f 100644
--- a/contrib/test/test-vectors-commit-sha.txt
+++ b/contrib/test/test-vectors-commit-sha.txt
@@ -1 +1 @@
-c2f0bc1d4153f8f962a808f27e36a048adbdaeff
+8c92099402fbf0d97538969d247b5bc5f457f3f1
diff --git a/src/flamenco/runtime/context/fd_exec_instr_ctx.c b/src/flamenco/runtime/context/fd_exec_instr_ctx.c
index e3232a11bd5..55225e14194 100644
--- a/src/flamenco/runtime/context/fd_exec_instr_ctx.c
+++ b/src/flamenco/runtime/context/fd_exec_instr_ctx.c
@@ -127,7 +127,7 @@ fd_exec_instr_ctx_get_signers( fd_exec_instr_ctx_t const * ctx,
                                fd_pubkey_t const *         signers[static FD_TXN_SIG_MAX] ) {
   ulong j = 0UL;
   for( ushort i=0; i<ctx->instr->acct_cnt && j<FD_TXN_SIG_MAX; i++ )
-    if( fd_instr_acc_is_signer_idx( ctx->instr, i ) ) {
+    if( fd_instr_acc_is_signer_idx( ctx->instr, i, NULL ) ) {
       ushort idx_in_txn = ctx->instr->accounts[i].index_in_transaction;
       int err = fd_exec_txn_ctx_get_key_of_account_at_index( ctx->txn_ctx,
                                                              idx_in_txn,
@@ -146,7 +146,7 @@ fd_exec_instr_ctx_any_signed( fd_exec_instr_ctx_t const * ctx,
   for( ushort j=0; j<ctx->instr->acct_cnt; j++ ) {
     ushort idx_in_txn = ctx->instr->accounts[ j ].index_in_transaction;
     is_signer |=
-      ( ( !!fd_instr_acc_is_signer_idx( ctx->instr, j ) ) &
+        ( ( !!fd_instr_acc_is_signer_idx( ctx->instr, j, NULL ) ) &
         ( 0==memcmp( pubkey->key, ctx->txn_ctx->account_keys[ idx_in_txn ].key, sizeof(fd_pubkey_t) ) ) );
   }
   return is_signer;
diff --git a/src/flamenco/runtime/fd_borrowed_account.h b/src/flamenco/runtime/fd_borrowed_account.h
index 7605c3503a4..244c9d5b0a3 100644
--- a/src/flamenco/runtime/fd_borrowed_account.h
+++ b/src/flamenco/runtime/fd_borrowed_account.h
@@ -318,7 +318,7 @@ fd_borrowed_account_is_signer( fd_borrowed_account_t const * borrowed_acct ) {
     return 0;
   }
 
-  return fd_instr_acc_is_signer_idx( instr, borrowed_acct->index_in_instruction );
+  return fd_instr_acc_is_signer_idx( instr, borrowed_acct->index_in_instruction, NULL );
 }
 
 /* fd_borrowed_account_is_writer mirrors the Agave function
diff --git a/src/flamenco/runtime/info/fd_instr_info.h b/src/flamenco/runtime/info/fd_instr_info.h
index 7339311aed5..8a1d05208da 100644
--- a/src/flamenco/runtime/info/fd_instr_info.h
+++ b/src/flamenco/runtime/info/fd_instr_info.h
@@ -109,23 +109,38 @@ fd_instr_info_init_from_txn_instr( fd_instr_info_t *      instr,
                                    fd_exec_txn_ctx_t *    txn_ctx,
                                    fd_txn_instr_t const * txn_instr );
 
+/* https://github.com/anza-xyz/solana-sdk/blob/589e6237f203c2719c300dc044f4e00f48e66a8f/message/src/versions/v0/loaded.rs#L152-L157 */
 FD_FN_PURE static inline int
 fd_instr_acc_is_writable_idx( fd_instr_info_t const * instr,
                               ushort                  idx ) {
   if( FD_UNLIKELY( idx>=instr->acct_cnt ) ) {
-    return FD_EXECUTOR_INSTR_ERR_MISSING_ACC;
+    return 0;
   }
 
   return !!(instr->accounts[idx].is_writable);
 }
 
+/* fd_instr_acc_is_signer_idx returns:
+    - 1 if account is signer
+    - 0 (with *out_opt_err==0) if account is not signer
+  If an error occurs during query, returns 0 and writes the
+  error code to *out_opt_err. Possible values for out_opt_err:
+    - FD_EXECUTOR_INSTR_ERR_MISSING_ACC occurs when the instr account
+      index provided is invalid (out of bounds).
+    - 0 if the query was successful. Check the return value to see
+      if the account is a signer.
+
+  https://github.com/firedancer-io/agave/blob/9e6bb8209d012e819e55ad90949dec17bc150fca/transaction-context/src/lib.rs#L782-L791    */
 FD_FN_PURE static inline int
 fd_instr_acc_is_signer_idx( fd_instr_info_t const * instr,
-                            ushort                  idx ) {
+                            ushort                  idx,
+                            int *                   out_opt_err ) {
   if( FD_UNLIKELY( idx>=instr->acct_cnt ) ) {
-    return FD_EXECUTOR_INSTR_ERR_MISSING_ACC;
+    if( out_opt_err ) *out_opt_err = FD_EXECUTOR_INSTR_ERR_MISSING_ACC;
+    return 0;
   }
 
+  if( out_opt_err ) *out_opt_err = 0;
   return !!(instr->accounts[idx].is_signer);
 }
 
diff --git a/src/flamenco/runtime/program/fd_address_lookup_table_program.c b/src/flamenco/runtime/program/fd_address_lookup_table_program.c
index 1c89e7e5559..d9485d447c4 100644
--- a/src/flamenco/runtime/program/fd_address_lookup_table_program.c
+++ b/src/flamenco/runtime/program/fd_address_lookup_table_program.c
@@ -225,7 +225,7 @@ create_lookup_table( fd_exec_instr_ctx_t *       ctx,
 
   /* https://github.com/solana-labs/solana/blob/v1.17.4/programs/address-lookup-table/src/processor.rs#L76-L83 */
   if( !FD_FEATURE_ACTIVE_BANK( ctx->txn_ctx->bank, relax_authority_signer_check_for_lookup_table_creation )
-      && !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY ) ) {
+      && !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY, NULL ) ) {
     fd_log_collector_msg_literal( ctx, "Authority account must be a signer" );
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
@@ -242,7 +242,7 @@ create_lookup_table( fd_exec_instr_ctx_t *       ctx,
   payer_key = payer_acct.acct->pubkey;
 
   /* https://github.com/solana-labs/solana/blob/v1.17.4/programs/address-lookup-table/src/processor.rs#L89-L92 */
-  if( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_PAYER ) ) {
+  if( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_PAYER, NULL ) ) {
     fd_log_collector_msg_literal( ctx, "Payer account must be a signer" );
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
@@ -491,7 +491,7 @@ freeze_lookup_table( fd_exec_instr_ctx_t * ctx ) {
   authority_key = authority_acct.acct->pubkey;
 
   /* https://github.com/solana-labs/solana/blob/v1.17.4/programs/address-lookup-table/src/processor.rs#L186-L189 */
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY ) ) ) {
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY, NULL ) ) ) {
     fd_log_collector_msg_literal( ctx, "Authority account must be a signer" );
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
@@ -599,7 +599,7 @@ extend_lookup_table( fd_exec_instr_ctx_t *       ctx,
   authority_key = authority_acct.acct->pubkey;
 
   /* https://github.com/solana-labs/solana/blob/v1.17.4/programs/address-lookup-table/src/processor.rs#L241-L244 */
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY ) ) ) {
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY, NULL ) ) ) {
     fd_log_collector_msg_literal( ctx, "Authority account must be a signer" );
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
@@ -728,7 +728,7 @@ extend_lookup_table( fd_exec_instr_ctx_t *       ctx,
 
     payer_key = payer_acct.acct->pubkey;
     /* https://github.com/solana-labs/solana/blob/v1.17.4/programs/address-lookup-table/src/processor.rs#L327-L330 */
-    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_PAYER ) ) ) {
+    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_PAYER, NULL ) ) ) {
       fd_log_collector_msg_literal( ctx, "Payer account must be a signer" );
       return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     }
@@ -823,7 +823,7 @@ deactivate_lookup_table( fd_exec_instr_ctx_t * ctx ) {
   authority_key = authority_acct.acct->pubkey;
 
   /* https://github.com/solana-labs/solana/blob/v1.17.4/programs/address-lookup-table/src/processor.rs#L356-L359 */
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY ) ) ) {
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY, NULL ) ) ) {
     fd_log_collector_msg_literal( ctx, "Authority account must be a signer" );
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
@@ -931,7 +931,7 @@ close_lookup_table( fd_exec_instr_ctx_t * ctx ) {
   authority_key = authority_acct.acct->pubkey;
 
   /* https://github.com/solana-labs/solana/blob/v1.17.4/programs/address-lookup-table/src/processor.rs#L405-L408 */
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY ) ) ) {
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_AUTHORITY, NULL ) ) ) {
     fd_log_collector_msg_literal( ctx, "Authority account must be a signer" );
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
diff --git a/src/flamenco/runtime/program/fd_bpf_loader_program.c b/src/flamenco/runtime/program/fd_bpf_loader_program.c
index 6af66b42365..223723fa231 100644
--- a/src/flamenco/runtime/program/fd_bpf_loader_program.c
+++ b/src/flamenco/runtime/program/fd_bpf_loader_program.c
@@ -355,7 +355,9 @@ common_close_account( fd_pubkey_t * authority_address,
   }
 
   /* https://github.com/anza-xyz/agave/blob/v2.1.14/programs/bpf_loader/src/lib.rs#L1319-L1322 */
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL ) ) ) {
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL, &err ) ) ) {
+    /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+    if( FD_UNLIKELY( !!err ) ) return err;
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
 
@@ -757,7 +759,9 @@ common_extend_program( fd_exec_instr_ctx_t * instr_ctx,
       }
 
       /* https://github.com/anza-xyz/agave/blob/v2.3.1/programs/bpf_loader/src/lib.rs#L1468-L1471 */
-      if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, AUTHORITY_ACCOUNT_INDEX ) ) ) {
+      if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, AUTHORITY_ACCOUNT_INDEX, &err ) ) ) {
+        /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+        if( FD_UNLIKELY( !!err ) ) return err;
         fd_log_collector_msg_literal( instr_ctx, "Upgrade authority did not sign" );
         return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
       }
@@ -997,7 +1001,9 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Incorrect buffer authority provided" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL ) ) ) {
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL, &err ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!err ) ) return err;
           fd_log_collector_msg_literal( instr_ctx, "Buffer authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
@@ -1129,7 +1135,9 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Buffer and upgrade authority don't match" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 7UL ) ) ) {
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 7UL, &err ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!err ) ) return err;
           fd_log_collector_msg_literal( instr_ctx, "Upgrade authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
@@ -1458,7 +1466,9 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Buffer and upgrade authority don't match" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 6UL ) ) ) {
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 6UL, &err ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!err ) ) return err;
           fd_log_collector_msg_literal( instr_ctx, "Upgrade authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
@@ -1524,7 +1534,9 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Incorrect upgrade authority provided" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 6UL ) ) ) {
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 6UL, &err ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!err ) ) return err;
           fd_log_collector_msg_literal( instr_ctx, "Upgrade authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
@@ -1684,7 +1696,9 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Incorrect buffer authority provided" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL ) ) ) {
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL, &err ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!err ) ) return err;
           fd_log_collector_msg_literal( instr_ctx, "Buffer authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
@@ -1709,7 +1723,9 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Incorrect upgrade authority provided" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL ) ) ) {
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL, &err ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!err ) ) return err;
           fd_log_collector_msg_literal( instr_ctx, "Upgrade authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
@@ -1780,11 +1796,17 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Incorrect buffer authority provided" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL ) ) ) {
+        int instr_err_code = 0;
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL, &instr_err_code ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!instr_err_code ) ) return instr_err_code;
           fd_log_collector_msg_literal( instr_ctx, "Buffer authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL ) ) ) {
+        instr_err_code = 0;
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL, &instr_err_code ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!instr_err_code ) ) return instr_err_code;
           fd_log_collector_msg_literal( instr_ctx, "New authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
@@ -1803,11 +1825,17 @@ process_loader_upgradeable_instruction( fd_exec_instr_ctx_t * instr_ctx ) {
           fd_log_collector_msg_literal( instr_ctx, "Incorrect upgrade authority provided" );
           return FD_EXECUTOR_INSTR_ERR_INCORRECT_AUTHORITY;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL ) ) ) {
+        int instr_err_code = 0;
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL, &instr_err_code ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!instr_err_code ) ) return instr_err_code;
           fd_log_collector_msg_literal( instr_ctx, "Upgrade authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
-        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL ) ) ) {
+        instr_err_code = 0;
+        if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL, &instr_err_code ) ) ) {
+          /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+          if( FD_UNLIKELY( !!instr_err_code ) ) return instr_err_code;
           fd_log_collector_msg_literal( instr_ctx, "New authority did not sign" );
           return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
         }
diff --git a/src/flamenco/runtime/program/fd_bpf_loader_serialization.c b/src/flamenco/runtime/program/fd_bpf_loader_serialization.c
index 42eac521bf4..bb7d939de65 100644
--- a/src/flamenco/runtime/program/fd_bpf_loader_serialization.c
+++ b/src/flamenco/runtime/program/fd_bpf_loader_serialization.c
@@ -249,7 +249,7 @@ fd_bpf_loader_input_serialize_aligned( fd_exec_instr_ctx_t *     ctx,
       /* https://github.com/anza-xyz/agave/blob/b5f5c3cdd3f9a5859c49ebc27221dc27e143d760/programs/bpf_loader/src/serialization.rs#L465 */
       fd_account_meta_t const * metadata = fd_borrowed_account_get_acc_meta( &view_acc );
 
-      uchar is_signer = (uchar)fd_instr_acc_is_signer_idx( ctx->instr, (uchar)i );
+      uchar is_signer = (uchar)fd_instr_acc_is_signer_idx( ctx->instr, (uchar)i, NULL );
       FD_STORE( uchar, serialized_params, is_signer );
       serialized_params += sizeof(uchar);
 
@@ -540,7 +540,7 @@ fd_bpf_loader_input_serialize_unaligned( fd_exec_instr_ctx_t *     ctx,
 
       fd_account_meta_t const * metadata = fd_borrowed_account_get_acc_meta( &view_acc );
 
-      uchar is_signer = (uchar)fd_instr_acc_is_signer_idx( ctx->instr, (uchar)i );
+      uchar is_signer = (uchar)fd_instr_acc_is_signer_idx( ctx->instr, (uchar)i, NULL );
       FD_STORE( uchar, serialized_params, is_signer );
       serialized_params += sizeof(uchar);
 
diff --git a/src/flamenco/runtime/program/fd_config_program.c b/src/flamenco/runtime/program/fd_config_program.c
index 16210bbc4f4..ca0aa8953d2 100644
--- a/src/flamenco/runtime/program/fd_config_program.c
+++ b/src/flamenco/runtime/program/fd_config_program.c
@@ -51,7 +51,7 @@ _process_config_instr( fd_exec_instr_ctx_t * ctx ) {
 
   /* https://github.com/solana-labs/solana/blob/v1.17.17/programs/config/src/config_processor.rs#L27 */
 
-  is_config_account_signer = fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_CONFIG );
+  is_config_account_signer = fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_CONFIG, NULL );
 
   /* https://github.com/solana-labs/solana/blob/v1.17.17/programs/config/src/config_processor.rs#L29-L31 */
 
@@ -128,7 +128,7 @@ _process_config_instr( fd_exec_instr_ctx_t * ctx ) {
 
       /* https://github.com/solana-labs/solana/blob/v1.17.17/programs/config/src/config_processor.rs#L72-L79 */
 
-      if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, (uchar)counter ) ) ) {
+      if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, (uchar)counter, NULL ) ) ) {
         /* Max msg_sz: 33 - 2 + 45 = 76 < 127 => we can use printf */
         fd_log_collector_printf_dangerous_max_127( ctx,
           "account %s signer_key().is_none()", FD_BASE58_ENC_32_ALLOCA( signer ) );
diff --git a/src/flamenco/runtime/program/fd_loader_v4_program.c b/src/flamenco/runtime/program/fd_loader_v4_program.c
index a3dab6a094d..3a394a73c92 100644
--- a/src/flamenco/runtime/program/fd_loader_v4_program.c
+++ b/src/flamenco/runtime/program/fd_loader_v4_program.c
@@ -92,7 +92,11 @@ check_program_account( fd_exec_instr_ctx_t *         instr_ctx,
   }
 
   /* https://github.com/anza-xyz/agave/blob/v2.2.6/programs/loader-v4/src/lib.rs#L75-L78 */
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL ) ) ) {
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL, err ) ) ) {
+    /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+    if( FD_UNLIKELY( !!(*err) ) ) {
+      return NULL;
+    }
     fd_log_collector_msg_literal( instr_ctx, "Authority did not sign" );
     *err = FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     return NULL;
@@ -314,7 +318,9 @@ fd_loader_v4_program_instruction_set_program_length( fd_exec_instr_ctx_t *
     }
 
     /* https://github.com/anza-xyz/agave/blob/v2.2.6/programs/loader-v4/src/lib.rs#L205-L208 */
-    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL ) ) ) {
+    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 1UL, &err ) ) ) {
+      /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+      if( FD_UNLIKELY( !!err ) ) return err;
       fd_log_collector_msg_literal( instr_ctx, "Authority did not sign" );
       return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     }
@@ -639,7 +645,9 @@ fd_loader_v4_program_instruction_transfer_authority( fd_exec_instr_ctx_t * instr
   }
 
   /* https://github.com/anza-xyz/agave/blob/v2.2.6/programs/loader-v4/src/lib.rs#L414-L417 */
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL ) ) ) {
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( instr_ctx->instr, 2UL, &err ) ) ) {
+    /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+    if( FD_UNLIKELY( !!err ) ) return err;
     fd_log_collector_msg_literal( instr_ctx, "New authority did not sign" );
     return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
   }
diff --git a/src/flamenco/runtime/program/fd_stake_program.c b/src/flamenco/runtime/program/fd_stake_program.c
index c5adaf65ec1..1c1c4ac0121 100644
--- a/src/flamenco/runtime/program/fd_stake_program.c
+++ b/src/flamenco/runtime/program/fd_stake_program.c
@@ -1362,7 +1362,7 @@ authorize_with_seed( fd_exec_instr_ctx_t const *   ctx,
   int                 rc;
   fd_pubkey_t const * signers[FD_TXN_SIG_MAX] = {0};
   fd_pubkey_t         out                     = {0};
-  if( FD_LIKELY( fd_instr_acc_is_signer_idx( ctx->instr, authority_base_index ) ) ) {
+  if( FD_LIKELY( fd_instr_acc_is_signer_idx( ctx->instr, authority_base_index, NULL ) ) ) {
 
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_state.rs#L289
     fd_pubkey_t const * base_pubkey = NULL;
@@ -1934,7 +1934,7 @@ move_stake_or_lamports_shared_checks( fd_exec_instr_ctx_t *   invoke_context, //
     int rc;
 
     // https://github.com/anza-xyz/agave/blob/cdff19c7807b006dd63429114fb1d9573bf74172/programs/stake/src/stake_state.rs#L145-L153
-    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( invoke_context->instr, stake_authority_index ) ) ) {
+    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( invoke_context->instr, stake_authority_index, NULL ) ) ) {
       return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     }
 
@@ -2251,7 +2251,7 @@ withdraw( fd_exec_instr_ctx_t const *   ctx,
   if( FD_UNLIKELY( rc ) ) return rc;
 
   // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_state.rs#L813
-  int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, withdraw_authority_index );
+  int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, withdraw_authority_index, NULL );
   if( FD_UNLIKELY( !is_signer ) ) return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
 
   // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_state.rs#L817
@@ -2333,7 +2333,7 @@ withdraw( fd_exec_instr_ctx_t const *   ctx,
   fd_pubkey_t custodian_pubkey_ = {0};
   fd_pubkey_t const * custodian_pubkey  = &custodian_pubkey_;
   if( custodian_index ) {
-    int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, *custodian_index );
+    int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, *custodian_index, NULL );
     if( is_signer ) {
       int err = fd_exec_instr_ctx_get_key_of_account_at_index( ctx, *custodian_index, &custodian_pubkey );
       if( FD_UNLIKELY( err ) ) return err;
@@ -2490,7 +2490,7 @@ get_optional_pubkey( fd_exec_instr_ctx_t *          ctx,
   // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L32
   if( FD_LIKELY( acc_idx<ctx->instr->acct_cnt ) ) {
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L33
-    if( FD_UNLIKELY( should_be_signer && !fd_instr_acc_is_signer_idx( ctx->instr, acc_idx ) ) ) {
+    if( FD_UNLIKELY( should_be_signer && !fd_instr_acc_is_signer_idx( ctx->instr, acc_idx, NULL ) ) ) {
       return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     }
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L39
@@ -2961,7 +2961,7 @@ fd_stake_program_execute( fd_exec_instr_ctx_t * ctx ) {
     if( FD_UNLIKELY( rc ) ) return rc;
 
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L237
-    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, 3 ) ) )
+    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, 3, NULL ) ) )
       return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L241
     fd_stake_authorized_t authorized = { .staker     = *staker_pubkey,
@@ -3013,7 +3013,7 @@ fd_stake_program_execute( fd_exec_instr_ctx_t * ctx ) {
     if( FD_UNLIKELY( rc ) ) return rc;
 
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L257
-    int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, 3 );
+    int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, 3, NULL );
     if( FD_UNLIKELY( !is_signer ) ) return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L260
     fd_pubkey_t const * custodian_pubkey = NULL;
@@ -3067,7 +3067,7 @@ fd_stake_program_execute( fd_exec_instr_ctx_t * ctx ) {
     if( FD_UNLIKELY( rc ) ) return rc;
 
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L281
-    int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, 3 );
+    int is_signer = fd_instr_acc_is_signer_idx( ctx->instr, 3, NULL );
     if( FD_UNLIKELY( !is_signer ) ) return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     // https://github.com/anza-xyz/agave/blob/c8685ce0e1bb9b26014f1024de2cd2b8c308cbde/programs/stake/src/stake_instruction.rs#L284
     fd_pubkey_t const * custodian_pubkey = NULL;
diff --git a/src/flamenco/runtime/program/fd_system_program.c b/src/flamenco/runtime/program/fd_system_program.c
index 1e9567bebbe..9088265583b 100644
--- a/src/flamenco/runtime/program/fd_system_program.c
+++ b/src/flamenco/runtime/program/fd_system_program.c
@@ -135,7 +135,10 @@ fd_system_program_transfer( fd_exec_instr_ctx_t * ctx,
 
   /* https://github.com/anza-xyz/agave/blob/v2.0.9/programs/system/src/system_processor.rs#L222-L232 */
 
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, from_acct_idx ) ) ) {
+  int instr_err_code = 0;
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, from_acct_idx, &instr_err_code ) ) ) {
+    /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+    if( FD_UNLIKELY( !!instr_err_code ) ) return instr_err_code;
     /* Max msg_sz: 37 - 2 + 45 = 80 < 127 => we can use printf */
     ushort idx_in_txn = ctx->instr->accounts[ from_acct_idx ].index_in_transaction;
     fd_log_collector_printf_dangerous_max_127( ctx,
@@ -572,7 +575,10 @@ fd_system_program_exec_transfer_with_seed( fd_exec_instr_ctx_t *
   ushort const from_base_idx = 1UL;
   ushort const to_idx        = 2UL;
 
-  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, from_base_idx ) ) ) {
+  int instr_err_code = 0;
+  if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, from_base_idx, &instr_err_code ) ) ) {
+    /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+    if( FD_UNLIKELY( !!instr_err_code ) ) return instr_err_code;
     /* Max msg_sz: 37 - 2 + 45 = 80 < 127 => we can use printf */
     ushort idx_in_txn = ctx->instr->accounts[ from_base_idx ].index_in_transaction;
     fd_log_collector_printf_dangerous_max_127( ctx,
diff --git a/src/flamenco/runtime/program/fd_vote_program.c b/src/flamenco/runtime/program/fd_vote_program.c
index 4d85afa2768..2e405ab5890 100644
--- a/src/flamenco/runtime/program/fd_vote_program.c
+++ b/src/flamenco/runtime/program/fd_vote_program.c
@@ -2195,7 +2195,7 @@ process_authorize_with_seed_instruction(
     return FD_EXECUTOR_INSTR_ERR_MISSING_ACC;
 
   // https://github.com/anza-xyz/agave/blob/v2.0.1/programs/vote/src/vote_processor.rs#L33
-  if( fd_instr_acc_is_signer_idx( ctx->instr, 2 ) ) {
+  if( fd_instr_acc_is_signer_idx( ctx->instr, 2, &rc ) ) {
 
     // https://github.com/anza-xyz/agave/blob/v2.1.14/programs/vote/src/vote_processor.rs#L34
     fd_pubkey_t const * base_pubkey = NULL;
@@ -2411,7 +2411,9 @@ fd_vote_program_execute( fd_exec_instr_ctx_t * ctx ) {
     if( FD_UNLIKELY( rc ) ) return rc;
 
     // https://github.com/anza-xyz/agave/blob/v2.0.1/programs/vote/src/vote_processor.rs#L116
-    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, 3 ) ) ) {
+    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, 3, &rc ) ) ) {
+      /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+      if( FD_UNLIKELY( !!rc ) ) break;
       // https://github.com/anza-xyz/agave/blob/v2.0.1/programs/vote/src/vote_processor.rs#L117
       rc = FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
       break;
@@ -2744,7 +2746,10 @@ fd_vote_program_execute( fd_exec_instr_ctx_t * ctx ) {
     if( FD_UNLIKELY( rc ) ) return rc;
 
     // https://github.com/anza-xyz/agave/blob/v2.0.1/programs/vote/src/vote_processor.rs#L239
-    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, 3 ) ) ) {
+    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, 3, &rc ) ) ) {
+      /* https://github.com/anza-xyz/agave/blob/v3.0.3/transaction-context/src/lib.rs#L789 */
+      if( FD_UNLIKELY( !!rc ) ) break;
+
       rc = FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
       break;
     }
diff --git a/src/flamenco/runtime/program/zksdk/fd_zksdk.c b/src/flamenco/runtime/program/zksdk/fd_zksdk.c
index 4ef16640aae..1d2a9586a21 100644
--- a/src/flamenco/runtime/program/zksdk/fd_zksdk.c
+++ b/src/flamenco/runtime/program/zksdk/fd_zksdk.c
@@ -18,11 +18,13 @@ fd_zksdk_process_close_context_state( fd_exec_instr_ctx_t * ctx ) {
   https://github.com/anza-xyz/agave/blob/master/programs/zk-elgamal-proof/src/lib.rs#L133-L141 */
   do {
     fd_guarded_borrowed_account_t owner_acc = {0};
-    FD_TRY_BORROW_INSTR_ACCOUNT_DEFAULT_ERR_CHECK( ctx, ACC_IDX_OWNER, &owner_acc );
-
-    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_OWNER ) ) ) {
+    int instr_err_code = 0;
+    if( FD_UNLIKELY( !fd_instr_acc_is_signer_idx( ctx->instr, ACC_IDX_OWNER, &instr_err_code ) ) ) {
+      if( FD_UNLIKELY( !!instr_err_code ) ) return instr_err_code;
       return FD_EXECUTOR_INSTR_ERR_MISSING_REQUIRED_SIGNATURE;
     }
+
+    FD_TRY_BORROW_INSTR_ACCOUNT_DEFAULT_ERR_CHECK( ctx, ACC_IDX_OWNER, &owner_acc );
     *owner_pubkey = *owner_acc.acct->pubkey;
     /* implicit drop of borrowed owner_acc */
   } while (0);