diff --git a/NEWS b/NEWS
index 70fe9e26f..29fdbb15a 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,7 @@ Version 5.x -- future
         * Change FT1000MP Mark V model names to align with FT1000MP
 
 Version 4.6
+        * Added RIG_FUNC_SYNC for FTDX101D/MP
         * Added Barrett 4100
         * Added DL2MAN (tr)uSDX -- needs refinement
         * Added Thetis entry -- derived from FlexRadio/Apache PowerSDR
diff --git a/src/misc.c b/src/misc.c
index 241765f32..c296e2972 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -740,6 +740,7 @@ static const struct
     { RIG_FUNC_SEND_MORSE, "SEND_MORSE" },
     { RIG_FUNC_SEND_VOICE_MEM, "SEND_VOICE_MEM" },
     { RIG_FUNC_OVF_STATUS, "OVF_STATUS" },
+    { RIG_FUNC_SYNC, "SYNC" },
     { RIG_FUNC_NONE, "" },
 };
 
diff --git a/src/sprintflst.c b/src/sprintflst.c
index ca87d8b6f..b6d70b125 100644
--- a/src/sprintflst.c
+++ b/src/sprintflst.c
@@ -177,6 +177,7 @@ int rig_sprintf_func(char *str, int nlen, setting_t func)
 
         if (!ms || !ms[0])
         {
+            rig_debug(RIG_EINTERNAL, "%s: unknown RIG_FUNC=%x\n", __func__, i);
             continue;    /* unknown, FIXME! */
         }