diff --git a/include/hamlib/rig.h b/include/hamlib/rig.h
index bef7936ce..b68447b45 100644
--- a/include/hamlib/rig.h
+++ b/include/hamlib/rig.h
@@ -471,7 +471,20 @@ typedef unsigned int vfo_t;
 #define RIG_TARGETABLE_FUNC (1<<4)
 #define RIG_TARGETABLE_ALL  0x7fffffff
 //! @endcond
-
+//
+//
+// Newer Icoms like the 9700 and 910 have VFOA/B on both Main & Sub
+// Compared to older rigs which have one or the other
+// So we need to distinguish between them
+//! @cond Doxygen_Suppress
+#define VFO_HAS_A_B ((rig->state.vfo_list & (RIG_VFO_A|RIG_VFO_B)) == (RIG_VFO_A|RIG_VFO_B))
+#define VFO_HAS_MAIN_SUB ((rig->state.vfo_list & (RIG_VFO_MAIN|RIG_VFO_SUB)) == (RIG_VFO_MAIN|RIG_VFO_SUB))
+#define VFO_HAS_MAIN_SUB_ONLY ((!VFO_HAS_A_B) & VFO_HAS_MAIN_SUB)
+#define VFO_HAS_MAIN_SUB_A_B_ONLY (VFO_HAS_A_B & VFO_HAS_MAIN_SUB)
+#define VFO_HAS_A_B_ONLY (VFO_HAS_A_B & (!VFO_HAS_MAIN_SUB))
+#define VFO_DUAL (RIG_VFO_MAIN_A|RIG_VFO_MAIN_B|RIG_VFO_SUB_A|RIG_VFO_SUB_B)
+#define VFO_HAS_DUAL ((rig->state.vfo_list & VFO_DUAL == VFO_DUAL)
+//! @endcond
 
 /**
  * \brief Macro for bandpass to be set to normal
@@ -2630,7 +2643,7 @@ rig_need_debug HAMLIB_PARAMS((enum rig_debug_level_e debug_level));
 #ifndef __cplusplus
 #ifdef __GNUC__
 // doing the debug macro with a dummy sprintf allows gcc to check the format string
-#define rig_debug(debug_level,fmt,...) { char xxxbuf[16384]="";snprintf(xxxbuf,sizeof(xxxbuf),fmt,__VA_ARGS__);rig_debug(debug_level,fmt,##__VA_ARGS__); }
+#define rig_debug(debug_level,fmt,...) { char xxxbuf[756]="";snprintf(xxxbuf,sizeof(xxxbuf),fmt,__VA_ARGS__);rig_debug(debug_level,fmt,##__VA_ARGS__); }
 #endif
 #endif
 extern HAMLIB_EXPORT(void)
diff --git a/rigs/icom/icom.c b/rigs/icom/icom.c
index 70583df08..8692bee5c 100644
--- a/rigs/icom/icom.c
+++ b/rigs/icom/icom.c
@@ -44,17 +44,6 @@
 #include "icom_defs.h"
 #include "frame.h"
 
-// Newer Icoms like the 9700 and 910 have VFOA/B on both Main & Sub
-// Compared to older rigs which have one or the other
-// So we need to distinguish between them
-#define VFO_HAS_A_B ((rig->state.vfo_list & (RIG_VFO_A|RIG_VFO_B)) == (RIG_VFO_A|RIG_VFO_B))
-#define VFO_HAS_MAIN_SUB ((rig->state.vfo_list & (RIG_VFO_MAIN|RIG_VFO_SUB)) == (RIG_VFO_MAIN|RIG_VFO_SUB))
-#define VFO_HAS_MAIN_SUB_ONLY ((!VFO_HAS_A_B) & VFO_HAS_MAIN_SUB)
-#define VFO_HAS_MAIN_SUB_A_B_ONLY (VFO_HAS_A_B & VFO_HAS_MAIN_SUB)
-#define VFO_HAS_A_B_ONLY (VFO_HAS_A_B & (!VFO_HAS_MAIN_SUB))
-#define VFO_DUAL (RIG_VFO_MAIN_A|RIG_VFO_MAIN_B|RIG_VFO_SUB_A|RIG_VFO_SUB_B)
-#define VFO_HAS_DUAL ((rig->state.vfo_list & VFO_DUAL == VFO_DUAL)
-
 static int set_vfo_curr(RIG *rig, vfo_t vfo, vfo_t curr_vfo);
 
 const cal_table_float_t icom_default_swr_cal =
@@ -1999,7 +1988,7 @@ int icom_set_vfo(RIG *rig, vfo_t vfo)
                   __func__);
         return -RIG_EINVAL;
     }
-
+rig_debug(RIG_DEBUG_TRACE,"%s: debug#1\n", __func__);
     if (vfo != priv->curr_vfo)
     {
         rig_debug(RIG_DEBUG_TRACE, "%s: VFO changing from %s to %s\n", __func__,
@@ -2007,6 +1996,7 @@ int icom_set_vfo(RIG *rig, vfo_t vfo)
         priv->curr_freq = 0; // reset curr_freq so set_freq works 1st time
     }
 
+rig_debug(RIG_DEBUG_TRACE,"%s: debug#2\n", __func__);
     switch (vfo)
     {
     case RIG_VFO_A:
@@ -2130,8 +2120,10 @@ int icom_set_vfo(RIG *rig, vfo_t vfo)
         return -RIG_EINVAL;
     }
 
+rig_debug(RIG_DEBUG_TRACE,"%s: debug#3\n", __func__);
     retval = icom_transaction(rig, C_SET_VFO, icvfo, NULL, 0,
                               ackbuf, &ack_len);
+rig_debug(RIG_DEBUG_TRACE,"%s: debug#4\n", __func__);
 
     if (retval != RIG_OK)
     {
@@ -2147,6 +2139,7 @@ int icom_set_vfo(RIG *rig, vfo_t vfo)
 
     priv->curr_vfo = vfo;
     rig->state.current_vfo = vfo;
+rig_debug(RIG_DEBUG_TRACE,"%s: debug#5\n", __func__);
     return RIG_OK;
 }
 
diff --git a/src/rig.c b/src/rig.c
index 60e938260..b18ba5040 100644
--- a/src/rig.c
+++ b/src/rig.c
@@ -1801,6 +1801,17 @@ int HAMLIB_API rig_set_vfo(RIG *rig, vfo_t vfo)
         return -RIG_EINVAL;
     }
 
+    // make sure we are asking for a VFO that the rig actually has
+    if ((vfo == RIG_VFO_A || vfo == RIG_VFO_B) && !VFO_HAS_A_B) {
+	rig_debug(RIG_DEBUG_ERR, "%s: rig does not have %s\n", __func__, rig_strvfo(vfo));
+	return -RIG_EINVAL;
+    }
+    if ((vfo == RIG_VFO_MAIN || vfo == RIG_VFO_SUB) && !VFO_HAS_MAIN_SUB)
+    {
+	rig_debug(RIG_DEBUG_ERR, "%s: rig does not have %s\n", __func__, rig_strvfo(vfo));
+	return -RIG_EINVAL;
+    }
+
     caps = rig->caps;
 
     if (caps->set_vfo == NULL)