diff --git a/src/serve/grpc/convert.rs b/src/serve/grpc/convert.rs
new file mode 100644
index 00000000..19b343b0
--- /dev/null
+++ b/src/serve/grpc/convert.rs
@@ -0,0 +1,12 @@
+use bytes::Bytes;
+use pallas::crypto::hash::Hash;
+use tonic::Status;
+
+pub fn bytes_to_hash32(data: &Bytes) -> Result<Hash<32>, Status> {
+    let array: [u8; 32] = data
+        .as_ref()
+        .try_into()
+        .map_err(|_| Status::invalid_argument("invalid hash value, needs to be 32-bytes long"))?;
+
+    Ok(Hash::<32>::new(array))
+}
diff --git a/src/serve/grpc/mod.rs b/src/serve/grpc/mod.rs
index 33304903..6d0a4228 100644
--- a/src/serve/grpc/mod.rs
+++ b/src/serve/grpc/mod.rs
@@ -9,6 +9,7 @@ use crate::ledger::store::LedgerStore;
 use crate::wal::redb::WalStore;
 use crate::{prelude::*, submit::Transaction};
 
+mod convert;
 mod query;
 mod submit;
 mod sync;
diff --git a/src/serve/grpc/query.rs b/src/serve/grpc/query.rs
index 0391bc21..ccdd2acd 100644
--- a/src/serve/grpc/query.rs
+++ b/src/serve/grpc/query.rs
@@ -1,7 +1,6 @@
 use crate::ledger::{store::LedgerStore, EraCbor, TxoRef};
 use futures_core::Stream;
-use itertools::Itertools;
-use pallas::crypto::hash::Hash;
+use itertools::Itertools as _;
 use pallas::interop::utxorpc as interop;
 use pallas::interop::utxorpc::spec as u5c;
 use pallas::ledger::traverse::MultiEraOutput;
@@ -23,11 +22,6 @@ impl QueryServiceImpl {
     }
 }
 
-fn bytes_to_hash(raw: &[u8]) -> Hash<32> {
-    let array: [u8; 32] = raw.try_into().unwrap();
-    Hash::<32>::new(array)
-}
-
 fn find_matching_set(
     ledger: &LedgerStore,
     query: u5c::cardano::TxOutputPattern,
@@ -47,6 +41,11 @@ fn find_matching_set(
     Ok(set)
 }
 
+fn from_u5c_txoref(txo: u5c::query::TxoRef) -> Result<TxoRef, Status> {
+    let hash = super::convert::bytes_to_hash32(&txo.hash)?;
+    Ok(TxoRef(hash, txo.index))
+}
+
 fn into_u5c_utxo(
     txo: &TxoRef,
     body: &EraCbor,
@@ -94,14 +93,15 @@ impl u5c::query::query_service_server::QueryService for QueryServiceImpl {
 
         info!("received new grpc query");
 
-        let keys = message
+        let keys: Vec<_> = message
             .keys
             .into_iter()
-            .map(|x| TxoRef(bytes_to_hash(&x.hash), x.index));
+            .map(from_u5c_txoref)
+            .try_collect()?;
 
         let utxos = self
             .ledger
-            .get_utxos(keys.collect_vec())
+            .get_utxos(keys)
             .map_err(|e| Status::internal(e.to_string()))?;
 
         let items: Vec<_> = utxos
diff --git a/src/serve/grpc/sync.rs b/src/serve/grpc/sync.rs
index 5d9cd95d..3a6d11fe 100644
--- a/src/serve/grpc/sync.rs
+++ b/src/serve/grpc/sync.rs
@@ -9,8 +9,11 @@ use tonic::{Request, Response, Status};
 use crate::ledger;
 use crate::wal::{self, RawBlock, WalReader as _};
 
-fn u5c_to_chain_point(block_ref: u5c::sync::BlockRef) -> wal::ChainPoint {
-    wal::ChainPoint::Specific(block_ref.index, block_ref.hash.as_ref().into())
+fn u5c_to_chain_point(block_ref: u5c::sync::BlockRef) -> Result<wal::ChainPoint, Status> {
+    Ok(wal::ChainPoint::Specific(
+        block_ref.index,
+        super::convert::bytes_to_hash32(&block_ref.hash)?,
+    ))
 }
 
 // fn raw_to_anychain2(raw: &[u8]) -> AnyChainBlock {
@@ -73,7 +76,11 @@ impl u5c::sync::chain_sync_service_server::ChainSyncService for ChainSyncService
     ) -> Result<Response<u5c::sync::FetchBlockResponse>, Status> {
         let message = request.into_inner();
 
-        let points: Vec<_> = message.r#ref.into_iter().map(u5c_to_chain_point).collect();
+        let points: Vec<_> = message
+            .r#ref
+            .into_iter()
+            .map(u5c_to_chain_point)
+            .try_collect()?;
 
         let out = self
             .wal
@@ -94,7 +101,7 @@ impl u5c::sync::chain_sync_service_server::ChainSyncService for ChainSyncService
     ) -> Result<Response<u5c::sync::DumpHistoryResponse>, Status> {
         let msg = request.into_inner();
 
-        let from = msg.start_token.map(u5c_to_chain_point);
+        let from = msg.start_token.map(u5c_to_chain_point).transpose()?;
 
         let len = msg.max_items as usize + 1;
 
@@ -145,7 +152,7 @@ impl u5c::sync::chain_sync_service_server::ChainSyncService for ChainSyncService
                 .intersect
                 .into_iter()
                 .map(u5c_to_chain_point)
-                .collect();
+                .try_collect()?;
 
             self.wal
                 .find_intersect(&intersect)