diff --git a/include/PSX/System/IOPorts/spu_io.hpp b/include/PSX/System/IOPorts/spu_io.hpp
index 1b7638a7..4fea5d37 100644
--- a/include/PSX/System/IOPorts/spu_io.hpp
+++ b/include/PSX/System/IOPorts/spu_io.hpp
@@ -46,10 +46,13 @@ namespace JabyEngine {
         };
         #pragma pack(pop)
 
+        // Required so GCC does not create guards for the ReverbON reference
+        #define __eon_declaration __new_declare_io_port(EchoIO, 0x1F801D98)
+
         static auto& Voice               = __new_declare_io_port_array(struct Voice, VoiceCount, 0x1F801C00);
         static auto& PMON                = __new_declare_io_port(PitchModulationIO,              0x1F801D90);
         static auto& NON                 = __new_declare_io_port(NoiseIO,                        0x1F801D94);
-        static auto& EON                 = __new_declare_io_port(EchoIO,                         0x1F801D98);
+        static auto& EON                 = __eon_declaration;
         static auto& SRAMTransferAdr     = __new_declare_io_port(SRAMAdrIO,                      0x1F801DA6);
         static auto& ControlRegister     = __new_declare_io_port(ControlRegisterIO,              0x1F801DAA);
         static auto& DataTransferControl = __new_declare_io_port(DataTransferControlIO,          0x1F801DAC);
@@ -81,7 +84,7 @@ namespace JabyEngine {
                 static inline auto& Left  = __new_declare_io_port(SimpleVolumeIO, 0x1F801D84);
                 static inline auto& Right = __new_declare_io_port(SimpleVolumeIO, 0x1F801D86);
             };
-            static inline auto& On          = EON;
+            static inline auto& On          = __eon_declaration;
             static inline auto& WorkAreaAdr = __new_declare_io_port(SRAMAdrIO, 0x1F801DA2);
         };
     }