diff --git a/libuavcan/include/uavcan/transport/transfer_receiver.hpp b/libuavcan/include/uavcan/transport/transfer_receiver.hpp
index 7e3fdaf09a..f73e616cd5 100644
--- a/libuavcan/include/uavcan/transport/transfer_receiver.hpp
+++ b/libuavcan/include/uavcan/transport/transfer_receiver.hpp
@@ -54,6 +54,8 @@ private:
 
     bool isInitialized() const { return iface_index_ != IfaceIndexNotSet; }
 
+    bool isMidTransfer() const { return buffer_write_pos_ > 0; }
+
     void registerError() const;
 
     TidRelation getTidRelation(const RxFrame& frame) const;
diff --git a/libuavcan/src/transport/uc_transfer_receiver.cpp b/libuavcan/src/transport/uc_transfer_receiver.cpp
index 9fc9e9b4e0..28df4c4eac 100644
--- a/libuavcan/src/transport/uc_transfer_receiver.cpp
+++ b/libuavcan/src/transport/uc_transfer_receiver.cpp
@@ -75,7 +75,7 @@ bool TransferReceiver::validate(const RxFrame& frame) const
         registerError();
         return false;
     }
-    if (frame.isStartOfTransfer() && (buffer_write_pos_ != 0))
+    if (frame.isStartOfTransfer() && isMidTransfer())
     {
         UAVCAN_TRACE("TransferReceiver", "Unexpected start of transfer, %s", frame.toString().c_str());
         registerError();