diff --git a/converter/ibmpc_usb/ibmpc_usb.cpp b/converter/ibmpc_usb/ibmpc_usb.cpp
index e4c0d75d..26d5feef 100644
--- a/converter/ibmpc_usb/ibmpc_usb.cpp
+++ b/converter/ibmpc_usb/ibmpc_usb.cpp
@@ -191,9 +191,8 @@ uint8_t IBMPCConverter::process_interface(void)
          * IBMPC_ERR_TIMEOUT        Reinit
          * IBMPC_ERR_FULL           Ignore
          * IBMPC_ERR_ILLEGAL        Reinit
-         * IBMPC_ERR_FF             Ignore(not used)
          */
-        // when recv error, neither send error nor buffer full
+        // send error and buffer full are ignored   TODO: refactor
         if (!(ibmpc.error & (IBMPC_ERR_SEND | IBMPC_ERR_FULL))) {
             state = ERROR;
             if (ibmpc.error == IBMPC_ERR_PARITY_AA) {
diff --git a/tmk_core/protocol/ibmpc.hpp b/tmk_core/protocol/ibmpc.hpp
index d1765e7f..6f2eceba 100644
--- a/tmk_core/protocol/ibmpc.hpp
+++ b/tmk_core/protocol/ibmpc.hpp
@@ -84,7 +84,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #define IBMPC_ERR_TIMEOUT     0x20
 #define IBMPC_ERR_FULL        0x40
 #define IBMPC_ERR_ILLEGAL     0x80
-#define IBMPC_ERR_FF          0xF0
 
 #define IBMPC_LED_SCROLL_LOCK 0
 #define IBMPC_LED_NUM_LOCK    1