diff --git a/lib/include/prjxray/xilinx/configuration.h b/lib/include/prjxray/xilinx/configuration.h
index 0a883547..4721f8db 100644
--- a/lib/include/prjxray/xilinx/configuration.h
+++ b/lib/include/prjxray/xilinx/configuration.h
@@ -75,6 +75,44 @@ class Configuration {
 	FrameMap frames_;
 };
 
+// The explicit specializations below are defined in configuration.cc.
+// They must be declared before use in every translation unit
+// ([temp.expl.spec]): without these declarations, a TU that calls
+// createType2ConfigurationPacketData<Spartan6> instantiates the primary
+// template defined further down in this header, and that COMDAT copy
+// collides with the strong definition from configuration.cc when linking
+// with mingw-w64 ld ("multiple definition"); ELF linkers silently
+// resolve the collision in favour of the strong symbol.
+template <>
+Configuration<Spartan6>::PacketData
+Configuration<Spartan6>::createType2ConfigurationPacketData(
+    const Frames<Spartan6>::Frames2Data& frames,
+    absl::optional<Spartan6::Part>& part);
+
+template <>
+void Configuration<Spartan6>::createConfigurationPackage(
+    Spartan6::ConfigurationPackage& out_packets,
+    const PacketData& packet_data,
+    absl::optional<Spartan6::Part>& part);
+
+template <>
+void Configuration<Series7>::createConfigurationPackage(
+    Series7::ConfigurationPackage& out_packets,
+    const PacketData& packet_data,
+    absl::optional<Series7::Part>& part);
+
+template <>
+void Configuration<UltraScale>::createConfigurationPackage(
+    UltraScale::ConfigurationPackage& out_packets,
+    const PacketData& packet_data,
+    absl::optional<UltraScale::Part>& part);
+
+template <>
+void Configuration<UltraScalePlus>::createConfigurationPackage(
+    UltraScalePlus::ConfigurationPackage& out_packets,
+    const PacketData& packet_data,
+    absl::optional<UltraScalePlus::Part>& part);
+
 template <typename ArchType>
 typename Configuration<ArchType>::PacketData
 Configuration<ArchType>::createType2ConfigurationPacketData(