diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg.c b/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg.c
index fd04b9abab..3a2bcf8b12 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg.c
@@ -39,7 +39,7 @@
 /* Virtual serial port over USB.*/
 SerialUSBDriver SDU1;
 
-cdc_linecoding_t linecoding = {
+static cdc_linecoding_t linecoding = {
   {0x00, 0x96, 0x00, 0x00},             /* 38400.                           */
   LC_STOP_1, LC_PARITY_NONE, 8
 };
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg_dualcdc.c b/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg_dualcdc.c
index c3c35e02d8..5a407d748d 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg_dualcdc.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/usbcfg_dualcdc.c
@@ -34,6 +34,10 @@
 
 #include "usbcfg.h"
 
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(_arr) (sizeof(_arr) / sizeof(_arr[0]))
+#endif
+
 #if defined(HAL_USB_PRODUCT_ID) && HAL_HAVE_DUAL_USB_CDC
 /*
  * Virtual serial ports over USB.
@@ -41,15 +45,14 @@
 SerialUSBDriver SDU1;
 SerialUSBDriver SDU2;
 
-cdc_linecoding_t linecoding = {
-  {0x00, 0x96, 0x00, 0x00},             /* 38400.                           */
-  LC_STOP_1, LC_PARITY_NONE, 8
+static cdc_linecoding_t linecoding[] = {
+  {{0x00, 0x96, 0x00, 0x00},             /* 38400.                           */
+  LC_STOP_1, LC_PARITY_NONE, 8},
+  {{0x00, 0x96, 0x00, 0x00},             /* 38400.                           */
+  LC_STOP_1, LC_PARITY_NONE, 8}
 };
 
-cdc_linecoding_t linecoding2 = {
-  {0x00, 0x96, 0x00, 0x00},             /* 38400.                           */
-  LC_STOP_1, LC_PARITY_NONE, 8
-};
+static uint8_t ep_index[] = {0, 2};
 
 /*
  * Endpoints.
@@ -303,11 +306,11 @@ static const USBDescriptor *get_descriptor(USBDriver *usbp,
 #if HAL_USE_SERIAL_USB
 uint32_t get_usb_baud(uint16_t endpoint_id)
 {
-    if(endpoint_id == 0)
-        return *((uint32_t*)linecoding.dwDTERate);
-    if(endpoint_id == 2)
-        return *((uint32_t*)linecoding2.dwDTERate);
-    return 0;
+  for (uint8_t i = 0; i < ARRAY_SIZE(linecoding); i++) {
+    if(endpoint_id == ep_index[i])
+        return *((uint32_t*)linecoding[i].dwDTERate);
+  }
+  return 0;
 }
 #endif
 /**
@@ -475,34 +478,23 @@ static bool requests_hook(USBDriver *usbp) {
     return true;
   }
   // process only index=2 commands here - ie the second interface - the first interface is handled via the default handler
-  if ((usbp->setup[0] & USB_RTYPE_TYPE_MASK) == USB_RTYPE_TYPE_CLASS && usbp->setup[4] == 0x02 && usbp->setup[5] == 0x00) {
-    switch (usbp->setup[1]) {
-    case CDC_GET_LINE_CODING:
-      usbSetupTransfer(usbp, (uint8_t *)&linecoding2, sizeof(linecoding2), NULL);
-      return true;
-    case CDC_SET_LINE_CODING:
-      usbSetupTransfer(usbp, (uint8_t *)&linecoding2, sizeof(linecoding2), NULL);
-      return true;
-    case CDC_SET_CONTROL_LINE_STATE:
-      /* Nothing to do, there are no control lines.*/
-      usbSetupTransfer(usbp, NULL, 0, NULL);
-      return true;
-    }
-  }
-  if ((usbp->setup[0] & USB_RTYPE_TYPE_MASK) == USB_RTYPE_TYPE_CLASS && usbp->setup[4] == 0x00 && usbp->setup[5] == 0x00) {
-    switch (usbp->setup[1]) {
-    case CDC_GET_LINE_CODING:
-      usbSetupTransfer(usbp, (uint8_t *)&linecoding, sizeof(linecoding), NULL);
-      return true;
-    case CDC_SET_LINE_CODING:
-      usbSetupTransfer(usbp, (uint8_t *)&linecoding, sizeof(linecoding), NULL);
-      return true;
-    case CDC_SET_CONTROL_LINE_STATE:
-      /* Nothing to do, there are no control lines.*/
-      usbSetupTransfer(usbp, NULL, 0, NULL);
-      return true;
+  for (uint8_t i = 0; i < ARRAY_SIZE(linecoding); i++) {
+    if ((usbp->setup[0] & USB_RTYPE_TYPE_MASK) == USB_RTYPE_TYPE_CLASS && usbp->setup[4] == ep_index[i] && usbp->setup[5] == 0x00) {
+      switch (usbp->setup[1]) {
+      case CDC_GET_LINE_CODING:
+        usbSetupTransfer(usbp, (uint8_t *)&linecoding[i], sizeof(linecoding[i]), NULL);
+        return true;
+      case CDC_SET_LINE_CODING:
+        usbSetupTransfer(usbp, (uint8_t *)&linecoding[i], sizeof(linecoding[i]), NULL);
+        return true;
+      case CDC_SET_CONTROL_LINE_STATE:
+        /* Nothing to do, there are no control lines.*/
+        usbSetupTransfer(usbp, NULL, 0, NULL);
+        return true;
+      }
     }
   }
+
   return sduRequestsHook(usbp);
 }