diff --git a/README.md b/README.md
index 38266ba..b02e82d 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ Otherwise, use toolchains included inside LPCxpresso. Like this.
 
     $ PATH=$PATH:/Applications/lpcxpresso_7.8.0_426/lpcxpresso/tools/bin
 
-## Build the firmware
+## Build firmware
 
 Fetch ChibiOS submodule into tree.
 
@@ -38,7 +38,7 @@ Just make in the top directory.
 
     $ make
 
-## Burn the firmware
+## Flash firmware
 
 Boot MCU in DFU mode. To do this, jumper BOOT0 pin at powering device.
 Then, burn firmware using dfu-util via USB.
diff --git a/main.c b/main.c
index 89a5035..2801dc7 100644
--- a/main.c
+++ b/main.c
@@ -35,6 +35,7 @@
 
 static void apply_error_term(void);
 static void apply_error_term_at(int i);
+static void cal_interpolate(int s);
 
 void sweep(void);
 
@@ -400,7 +401,7 @@ properties_t current_props = {
     { 1, TRC_PHASE,  1, 0, 1.0, 4.0 }
   },
   /* markers[4] */ {
-  { 1, 30 }, { 0, 40 }, { 0, 60 }, { 0, 80 }
+    { 1, 30, 0 }, { 0, 40, 0 }, { 0, 60, 0 }, { 0, 80, 0 }
   },
   /* active_marker */      0,
   /* checksum */           0
@@ -495,6 +496,37 @@ void sweep(void)
   //  apply_error_term();
 }
 
+static void
+update_marker_index(void)
+{
+  int m;
+  int i;
+  for (m = 0; m < 4; m++) {
+    if (!markers[m].enabled)
+      continue;
+    uint32_t f = markers[m].frequency;
+    if (f < frequencies[0]) {
+      markers[m].index = 0;
+      markers[m].frequency = frequencies[0];
+    } else if (f >= frequencies[sweep_points-1]) {
+      markers[m].index = sweep_points-1;
+      markers[m].frequency = frequencies[sweep_points-1];
+    } else {
+      for (i = 0; i < sweep_points-1; i++) {
+        if (frequencies[i] <= f && f < frequencies[i+1]) {
+          uint32_t mid = (frequencies[i] + frequencies[i+1])/2;
+          if (f < mid) {
+            markers[m].index = i;
+          } else {
+            markers[m].index = i + 1;
+          }
+          break;
+        }
+      }      
+    }
+  }
+}
+
 void
 update_frequencies(void)
 {
@@ -516,6 +548,8 @@ update_frequencies(void)
 
   if (cal_auto_interpolate)
     cal_interpolate(0);
+
+  update_marker_index();
   
   frequency_updated = TRUE;
   // set grid layout
@@ -1287,7 +1321,7 @@ static void cmd_marker(BaseSequentialStream *chp, int argc, char *argv[])
   if (argc == 0) {
     for (t = 0; t < 4; t++) {
       if (markers[t].enabled) {
-        chprintf(chp, "%d %d\r\n", t+1, markers[t].index);
+        chprintf(chp, "%d %d %d\r\n", t+1, markers[t].index, markers[t].frequency);
       }
     }
     return;
@@ -1303,7 +1337,7 @@ static void cmd_marker(BaseSequentialStream *chp, int argc, char *argv[])
   if (t < 0 || t >= 4)
     goto usage;
   if (argc == 1) {
-    chprintf(chp, "%d %d\r\n", t+1, markers[t].index);
+    chprintf(chp, "%d %d %d\r\n", t+1, markers[t].index, frequency);
     active_marker = t;
     markers[t].enabled = TRUE;
     return;
@@ -1320,6 +1354,7 @@ static void cmd_marker(BaseSequentialStream *chp, int argc, char *argv[])
       markers[t].enabled = TRUE;
       int index = atoi(argv[1]);
       markers[t].index = index;
+      markers[t].frequency = frequencies[index];
       active_marker = t;
     }
   }
diff --git a/nanovna.h b/nanovna.h
index d56950a..553f382 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -195,9 +195,9 @@ void set_trace_refpos(int t, float refpos);
 // marker
 
 typedef struct {
-  int enabled;
-  //uint32_t frequency;
-  int index;
+  int8_t enabled;
+  int16_t index;
+  uint32_t frequency;
 } marker_t;
 
 //extern marker_t markers[4];
diff --git a/ui.c b/ui.c
index 6ea3a01..cdde840 100644
--- a/ui.c
+++ b/ui.c
@@ -645,6 +645,7 @@ menu_marker_op_cb(int item)
     break;
   }
   ui_mode_normal();
+  draw_cal_status();
   //redraw_all();
 }
 
@@ -702,7 +703,6 @@ const menuitem_t menu_cal[] = {
   { MT_SUBMENU, "CALIBRATE", menu_calop },
   { MT_CALLBACK, "RESET", menu_cal2_cb },
   { MT_CALLBACK, "CORRECTION", menu_cal2_cb },
-  { MT_SUBMENU, "SAVE", menu_save },
   { MT_CANCEL, "BACK", NULL },
   { MT_NONE, NULL, NULL } // sentinel
 };
@@ -805,17 +805,23 @@ const menuitem_t menu_recall[] = {
   { MT_CALLBACK, "RECALL 2", menu_recall_cb },
   { MT_CALLBACK, "RECALL 3", menu_recall_cb },
   { MT_CALLBACK, "RECALL 4", menu_recall_cb },
-  { MT_SUBMENU, "SAVE", menu_save },
   { MT_CANCEL, "BACK", NULL },
   { MT_NONE, NULL, NULL } // sentinel
 };
 
+const menuitem_t menu_recall_save[] = {
+  { MT_SUBMENU, "RECALL", menu_recall },
+  { MT_SUBMENU, "SAVE", menu_save },
+  { MT_CANCEL, "BACK", NULL },
+  { MT_NONE, NULL, NULL } // sentinel
+};
+  
 const menuitem_t menu_top[] = {
   { MT_SUBMENU, "DISPLAY", menu_display },
   { MT_SUBMENU, "MARKER", menu_marker },
   { MT_SUBMENU, "STIMULUS", menu_stimulus },
   { MT_SUBMENU, "CAL", menu_cal },
-  { MT_SUBMENU, "\2RECALL\0/SAVE", menu_recall },
+  { MT_SUBMENU, "\2RECALL\0SAVE", menu_recall_save },
   { MT_CLOSE, "CLOSE", NULL },
   { MT_NONE, NULL, NULL } // sentinel
 };
@@ -1176,10 +1182,12 @@ ui_process_normal(void)
         if (active_marker >= 0 && markers[active_marker].enabled) {
           if ((status & EVT_DOWN) && markers[active_marker].index > 0) {
             markers[active_marker].index--;
+            markers[active_marker].frequency = frequencies[markers[active_marker].index];
             redraw_marker(active_marker, FALSE);
           }
           if ((status & EVT_UP) && markers[active_marker].index < 100) {
             markers[active_marker].index++;
+            markers[active_marker].frequency = frequencies[markers[active_marker].index];
             redraw_marker(active_marker, FALSE);
           }
         }
@@ -1384,6 +1392,7 @@ void drag_marker(int t, int m)
     index = search_nearest_index(touch_x, touch_y, t);
     if (index >= 0) {
       markers[m].index = index;
+      markers[m].frequency = frequencies[index];
       redraw_marker(m, TRUE);
     }
 
@@ -1419,6 +1428,7 @@ touch_pickup_marker(void)
 
       if (sq_distance(x - touch_x, y - touch_y) < 400) {
         if (active_marker != m) {
+          previous_marker = active_marker;
           active_marker = m;
           redraw_marker(active_marker, TRUE);
         }