diff --git a/9_Firmware/9_1_Microcontroller/9_1_1_C_Cpp_Libraries/ad9523.c b/9_Firmware/9_1_Microcontroller/9_1_1_C_Cpp_Libraries/ad9523.c
index a88e3dc..926b5ab 100644
--- a/9_Firmware/9_1_Microcontroller/9_1_1_C_Cpp_Libraries/ad9523.c
+++ b/9_Firmware/9_1_Microcontroller/9_1_1_C_Cpp_Libraries/ad9523.c
@@ -704,7 +704,13 @@ int32_t ad9523_setup(struct ad9523_dev **device,
 			 AD9523_READBACK_CTRL,
 			 0x0);
 	ad9523_io_update(dev);
-	ad9523_calibrate(dev);
+	/* F-4.6: capture VCO calibration result. Without this, a failed
+	 * calibration (e.g. target VCO outside the 3.6-4.0 GHz band) is
+	 * silently swallowed and downstream relies on PLL2_LD alone in
+	 * ad9523_status(), which can pass spuriously. */
+	ret = ad9523_calibrate(dev);
+	if (ret < 0)
+		return ret;
 	ad9523_sync(dev);
 
 	*device = dev;
diff --git a/9_Firmware/9_1_Microcontroller/9_1_3_C_Cpp_Code/main.cpp b/9_Firmware/9_1_Microcontroller/9_1_3_C_Cpp_Code/main.cpp
index e226a7c..9cc45a1 100644
--- a/9_Firmware/9_1_Microcontroller/9_1_3_C_Cpp_Code/main.cpp
+++ b/9_Firmware/9_1_Microcontroller/9_1_3_C_Cpp_Code/main.cpp
@@ -243,6 +243,11 @@ IWDG_HandleTypeDef hiwdg;
 ADF4382A_Manager lo_manager;
 extern SPI_HandleTypeDef hspi4;
 
+// AD9523 device handle. Retained at file scope so the recovery path can free
+// the previous instance before re-running setup (F-4.5: ad9523_setup() malloc's
+// a new dev + SPI desc each call; without retention each recovery cycle leaks).
+static struct ad9523_dev *g_ad9523_dev = NULL;
+
 //ADAR1000
 
 ADAR1000Manager adarManager;
@@ -1420,6 +1425,14 @@ static int configure_ad9523(void)
     int32_t ret;
     struct ad9523_dev *dev = NULL;
 
+    // F-4.5: recovery path re-runs configure_ad9523(); free the previous
+    // dev/SPI-desc allocation before letting setup() malloc a new pair.
+    if (g_ad9523_dev != NULL) {
+        DIAG("CLK", "Releasing previous ad9523_dev before re-setup");
+        ad9523_remove(g_ad9523_dev);
+        g_ad9523_dev = NULL;
+    }
+
     static struct ad9523_platform_data pdata;
     memset(&pdata, 0, sizeof(pdata));
 
@@ -1614,7 +1627,8 @@ static int configure_ad9523(void)
     ad9523_sync(dev);
     DIAG("CLK", "AD9523 configuration complete -- all outputs should be active");
 
-    // keep device pointer globally if needed (dev)
+    // F-4.5: retain the dev handle so recovery can free it before re-setup.
+    g_ad9523_dev = dev;
     return 0;
 }