diff --git a/tmk_core/protocol/ibmpc.cpp b/tmk_core/protocol/ibmpc.cpp
index df09cb9800..e9af15c653 100644
--- a/tmk_core/protocol/ibmpc.cpp
+++ b/tmk_core/protocol/ibmpc.cpp
@@ -204,7 +204,7 @@ void IBMPC::host_isr_clear(void)
     ringbuf_reset();
 }
 
-inline void IBMPC::isr(void)
+void IBMPC::isr(void)
 {
     uint8_t dbit;
     dbit = IBMPC_DATA_PIN&(1<<data_bit);
diff --git a/tmk_core/protocol/ibmpc.hpp b/tmk_core/protocol/ibmpc.hpp
index 960a980c58..d1765e7f09 100644
--- a/tmk_core/protocol/ibmpc.hpp
+++ b/tmk_core/protocol/ibmpc.hpp
@@ -118,7 +118,7 @@ class IBMPC
             clock_mask(1 << clock), data_mask(1 << data) {
     };
 
-    inline void isr(void) __attribute__((__always_inline__));
+    void isr(void);
 
 
     private: