diff --git a/pkg/hold/pds/xrpc_test.go b/pkg/hold/pds/xrpc_test.go
index 6da962b..d4e798c 100644
--- a/pkg/hold/pds/xrpc_test.go
+++ b/pkg/hold/pds/xrpc_test.go
@@ -220,6 +220,27 @@ func decodeFirehoseMessage(t *testing.T, message []byte) (*events.EventHeader, *
 	return &header, &commit
 }
 
+// skipAccountEvent reads and discards the initial #account event that the
+// EventBroadcaster sends to every new subscriber.
+func skipAccountEvent(t *testing.T, conn *websocket.Conn) {
+	t.Helper()
+	msgType, message, err := conn.ReadMessage()
+	if err != nil {
+		t.Fatalf("Failed to read account event: %v", err)
+	}
+	if msgType != websocket.BinaryMessage {
+		t.Fatalf("Expected binary message for account event, got type %d", msgType)
+	}
+	reader := bytes.NewReader(message)
+	var header events.EventHeader
+	if err := header.UnmarshalCBOR(reader); err != nil {
+		t.Fatalf("Failed to decode account event header: %v", err)
+	}
+	if header.MsgType != "#account" {
+		t.Fatalf("Expected #account event, got %s", header.MsgType)
+	}
+}
+
 // assertCARResponse validates CAR file response
 func assertCARResponse(t *testing.T, w *httptest.ResponseRecorder, expectedCode int) []byte {
 	t.Helper()
@@ -2851,6 +2872,9 @@ func TestHandleSubscribeRepos(t *testing.T) {
 		}
 		defer conn.Close()
 
+		// Skip the initial #account event
+		skipAccountEvent(t, conn)
+
 		// Should receive the 3 historical events
 		for i := 0; i < 3; i++ {
 			messageType, message, err := conn.ReadMessage()
@@ -2890,6 +2914,9 @@ func TestHandleSubscribeRepos(t *testing.T) {
 		}
 		defer conn.Close()
 
+		// Skip the initial #account event
+		skipAccountEvent(t, conn)
+
 		// Should only receive event 3 (after cursor=2)
 		messageType, message, err := conn.ReadMessage()
 		if err != nil {
@@ -2926,6 +2953,9 @@ func TestHandleSubscribeRepos(t *testing.T) {
 		}
 		defer conn.Close()
 
+		// Skip the initial #account event
+		skipAccountEvent(t, conn)
+
 		// Verify no historical events by broadcasting immediately and checking
 		// that we only receive the new event (not historical ones)
 		// Give subscriber time to register first
@@ -2978,6 +3008,9 @@ func TestHandleSubscribeRepos(t *testing.T) {
 		}
 		defer conn.Close()
 
+		// Skip the initial #account event
+		skipAccountEvent(t, conn)
+
 		// Read and discard the 4 historical events (seq 1-4)
 		for i := 0; i < 4; i++ {
 			_, _, err := conn.ReadMessage()
diff --git a/pkg/s3/types.go b/pkg/s3/types.go
index 20f0c5b..19da9cd 100644
--- a/pkg/s3/types.go
+++ b/pkg/s3/types.go
@@ -192,6 +192,11 @@ func NewS3Service(params map[string]any) (*S3Service, error) {
 			o.BaseEndpoint = aws.String(endpoint)
 			o.UsePathStyle = true
 		}
+		// Disable automatic CRC32 checksum calculation on uploads.
+		// SDK v2 v1.71.0+ adds checksums by default using chunked encoding
+		// with trailers, which causes XAmzContentSHA256Mismatch errors on
+		// S3-compatible services that don't support this.
+		o.RequestChecksumCalculation = aws.RequestChecksumCalculationWhenRequired
 	})
 
 	var s3PathPrefix string