diff --git a/cores/arduino/USBCore.cpp b/cores/arduino/USBCore.cpp
index 691a7a96..5f88ef51 100644
--- a/cores/arduino/USBCore.cpp
+++ b/cores/arduino/USBCore.cpp
@@ -54,8 +54,17 @@
 bool USBDeviceClass::begin()
 {
 #if defined(USB_CLASS)
+    #if defined(STM32L0_CONFIG_PIN_VBUS_HAS_DIVIDER)
+    // On boards with an external divider (to allow measuring
+    // voltage rather than just on/off), do not enable the pulldown
+    // since that influences the divider (and the divider works as
+    // an external pulldown too).
+    bool needs_pulldown = false;
+    #else
+    bool needs_pulldown = true;
+    #endif
     return USBD_Initialize(USB_VID, USB_PID, (const uint8_t*)USB_MANUFACTURER, (const uint8_t*)USB_PRODUCT, USB_CLASS,
-                           STM32L0_CONFIG_PIN_VBUS, STM32L0_USB_IRQ_PRIORITY,
+                           STM32L0_CONFIG_PIN_VBUS, needs_pulldown, STM32L0_USB_IRQ_PRIORITY,
                            &USBDeviceClass::connectCallback, &USBDeviceClass::disconnectCallback, &USBDeviceClass::suspendCallback, &USBDeviceClass::resumeCallback);
 #endif
     return false;
diff --git a/cores/arduino/wiring.c b/cores/arduino/wiring.c
index 594695a5..0d593a78 100644
--- a/cores/arduino/wiring.c
+++ b/cores/arduino/wiring.c
@@ -64,12 +64,6 @@ void init( void )
 
     stm32l0_dma_configure(STM32L0_ADC_IRQ_PRIORITY, STM32L0_UART_IRQ_PRIORITY, STM32L0_UART_IRQ_PRIORITY);
 
-#if defined(STM32L0_CONFIG_PIN_VBUS)
-    if (STM32L0_CONFIG_PIN_VBUS != STM32L0_GPIO_PIN_NONE) {
-        stm32l0_gpio_pin_configure(STM32L0_CONFIG_PIN_VBUS, (STM32L0_GPIO_PARK_HIZ | STM32L0_GPIO_PUPD_PULLDOWN | STM32L0_GPIO_OSPEED_LOW | STM32L0_GPIO_OTYPE_PUSHPULL | STM32L0_GPIO_MODE_INPUT));
-    }
-#endif
-
 #if defined(STM32L0_CONFIG_PIN_VBAT)
     stm32l0_gpio_pin_configure(STM32L0_CONFIG_PIN_VBAT, (STM32L0_GPIO_PARK_NONE | STM32L0_GPIO_MODE_ANALOG));
 #endif
diff --git a/cores/arduino/wiring_private.h b/cores/arduino/wiring_private.h
index 8af973de..be299c9b 100644
--- a/cores/arduino/wiring_private.h
+++ b/cores/arduino/wiring_private.h
@@ -59,7 +59,7 @@ extern void USBD_CDC_Initialize(void *);
 extern void USBD_CDC_MSC_Initialize(void *);
 
 extern bool USBD_Initialize(uint16_t vid, uint16_t pid, const uint8_t *manufacturer, const uint8_t *product, void(*initialize)(void *),
-                            unsigned int pin_vbus, unsigned int priority,
+                            unsigned int pin_vbus, bool pin_vbus_needs_pulldown, unsigned int priority,
                             void(*connect_callback)(void), void(*disconnect_callback)(void), void(*suspend_callback)(void), void(*resume_callback)(void));
 extern void USBD_Teardown(void);
 extern void USBD_Attach(void);
diff --git a/system/STM32L0xx/Lib/libstm32l052xx.a b/system/STM32L0xx/Lib/libstm32l052xx.a
index 49a774bd..a69a9074 100644
Binary files a/system/STM32L0xx/Lib/libstm32l052xx.a and b/system/STM32L0xx/Lib/libstm32l052xx.a differ
diff --git a/system/STM32L0xx/Lib/libstm32l072xx.a b/system/STM32L0xx/Lib/libstm32l072xx.a
index 210bb454..0f27b4e9 100644
Binary files a/system/STM32L0xx/Lib/libstm32l072xx.a and b/system/STM32L0xx/Lib/libstm32l072xx.a differ
diff --git a/system/STM32L0xx/Lib/libstm32l082xx.a b/system/STM32L0xx/Lib/libstm32l082xx.a
index 8d7b8ace..724ceef1 100644
Binary files a/system/STM32L0xx/Lib/libstm32l082xx.a and b/system/STM32L0xx/Lib/libstm32l082xx.a differ
diff --git a/system/STM32L0xx/Source/USB/usbd_conf.c b/system/STM32L0xx/Source/USB/usbd_conf.c
index eaf5d6fe..c7ba3f6f 100644
--- a/system/STM32L0xx/Source/USB/usbd_conf.c
+++ b/system/STM32L0xx/Source/USB/usbd_conf.c
@@ -182,7 +182,7 @@ static void USBD_VBUSChangedIrq(void)
 }
 
 bool USBD_Initialize(uint16_t vid, uint16_t pid, const uint8_t *manufacturer, const uint8_t *product, void(*initialize)(struct _USBD_HandleTypeDef *),
-                     unsigned int pin_vbus, unsigned int priority,
+                     unsigned int pin_vbus, bool pin_vbus_needs_pulldown, unsigned int priority,
                      void(*connect_callback)(void), void(*disconnect_callback)(void), void(*suspend_callback)(void), void(*resume_callback)(void))
 {
     if (stm32l0_system_pclk1() < 10000000)
@@ -198,9 +198,6 @@ bool USBD_Initialize(uint16_t vid, uint16_t pid, const uint8_t *manufacturer, co
     USBD_ProductString = product;
     USBD_ClassInitialize = initialize;
     
-    usbd_pin_vbus = pin_vbus;
-    usbd_mask_vbus = 1 << ((pin_vbus & STM32L0_GPIO_PIN_INDEX_MASK) >> STM32L0_GPIO_PIN_INDEX_SHIFT);
-    
     /* Set USB Interrupt priority */
     NVIC_SetPriority(USB_IRQn, priority);
 
@@ -209,19 +206,32 @@ bool USBD_Initialize(uint16_t vid, uint16_t pid, const uint8_t *manufacturer, co
     usbd_suspend_callback = suspend_callback;
     usbd_resume_callback = resume_callback;
     
-    stm32l0_lptim_timeout_create(&USBD_VBUSTimeout);
-
     /* Configure USB FS GPIOs */
-    stm32l0_gpio_pin_configure(usbd_pin_vbus, (STM32L0_GPIO_PARK_HIZ | STM32L0_GPIO_PUPD_PULLDOWN | STM32L0_GPIO_OSPEED_LOW | STM32L0_GPIO_OTYPE_PUSHPULL | STM32L0_GPIO_MODE_INPUT));
+    usbd_pin_vbus = pin_vbus;
+    if (pin_vbus != STM32L0_GPIO_PIN_NONE) {
+        usbd_mask_vbus = 1 << ((pin_vbus & STM32L0_GPIO_PIN_INDEX_MASK) >> STM32L0_GPIO_PIN_INDEX_SHIFT);
 
-    if (stm32l0_gpio_pin_read(usbd_pin_vbus))
-    {
-        stm32l0_lptim_timeout_start(&USBD_VBUSTimeout, stm32l0_lptim_millis_to_ticks(40), (stm32l0_lptim_callback_t)USBD_VBUSTimeoutIrq); /* 40ms */
+        stm32l0_lptim_timeout_create(&USBD_VBUSTimeout);
+
+        uint32_t mode = (STM32L0_GPIO_PARK_HIZ | STM32L0_GPIO_OSPEED_LOW | STM32L0_GPIO_OTYPE_PUSHPULL | STM32L0_GPIO_MODE_INPUT);
+        if (pin_vbus_needs_pulldown)
+            mode |= STM32L0_GPIO_PUPD_PULLDOWN;
+        stm32l0_gpio_pin_configure(usbd_pin_vbus, mode);
+
+        if (stm32l0_gpio_pin_read(usbd_pin_vbus))
+        {
+            stm32l0_lptim_timeout_start(&USBD_VBUSTimeout, stm32l0_lptim_millis_to_ticks(40), (stm32l0_lptim_callback_t)USBD_VBUSTimeoutIrq); /* 40ms */
+        }
+        
+        stm32l0_exti_attach(usbd_pin_vbus,
+                            (STM32L0_EXTI_CONTROL_NOWAKEUP | STM32L0_EXTI_CONTROL_PRIORITY_LOW | STM32L0_EXTI_CONTROL_EDGE_RISING | STM32L0_EXTI_CONTROL_EDGE_FALLING),
+                            (stm32l0_exti_callback_t)USBD_VBUSChangedIrq, NULL);
+    } else {
+        // No VBUS pin, assume VBUS is always present
+        usbd_attached = true;
+        usbd_mask_vbus = 0;
     }
-    
-    stm32l0_exti_attach(usbd_pin_vbus,
-                        (STM32L0_EXTI_CONTROL_NOWAKEUP | STM32L0_EXTI_CONTROL_PRIORITY_LOW | STM32L0_EXTI_CONTROL_EDGE_RISING | STM32L0_EXTI_CONTROL_EDGE_FALLING),
-                        (stm32l0_exti_callback_t)USBD_VBUSChangedIrq, NULL);
+        
     
     return true;
 }
@@ -230,11 +240,13 @@ void USBD_Teardown()
 {
     USBD_Detach();
 
-    stm32l0_exti_detach(usbd_pin_vbus);
+    if (usbd_pin_vbus != STM32L0_GPIO_PIN_NONE) {
+        stm32l0_exti_detach(usbd_pin_vbus);
 
-    stm32l0_lptim_timeout_stop(&USBD_VBUSTimeout);
+        stm32l0_lptim_timeout_stop(&USBD_VBUSTimeout);
 
-    stm32l0_gpio_pin_configure(usbd_pin_vbus, STM32L0_GPIO_MODE_ANALOG);
+        stm32l0_gpio_pin_configure(usbd_pin_vbus, STM32L0_GPIO_MODE_ANALOG);
+    }
 
     usbd_wakeup = false;
     usbd_enabled = false;
@@ -370,16 +382,18 @@ void USBD_SetupVBUS(bool wakeup)
     {
         usbd_wakeup = wakeup;
 
-        stm32l0_exti_detach(usbd_pin_vbus);
-        
-        stm32l0_gpio_pin_configure(usbd_pin_vbus,
-                                   (usbd_wakeup ? STM32L0_GPIO_PARK_NONE : STM32L0_GPIO_PARK_HIZ) |
-                                   (STM32L0_GPIO_PUPD_PULLDOWN | STM32L0_GPIO_OSPEED_LOW | STM32L0_GPIO_OTYPE_PUSHPULL | STM32L0_GPIO_MODE_INPUT));
-
-        stm32l0_exti_attach(usbd_pin_vbus,
-                            ((usbd_wakeup ? 0 : STM32L0_EXTI_CONTROL_NOWAKEUP) |
-                             (STM32L0_EXTI_CONTROL_PRIORITY_LOW | STM32L0_EXTI_CONTROL_EDGE_RISING | STM32L0_EXTI_CONTROL_EDGE_FALLING)),
-                            (stm32l0_exti_callback_t)USBD_VBUSChangedIrq, NULL);
+        if (usbd_pin_vbus != STM32L0_GPIO_PIN_NONE) {
+            stm32l0_exti_detach(usbd_pin_vbus);
+            
+            stm32l0_gpio_pin_configure(usbd_pin_vbus,
+                                       (usbd_wakeup ? STM32L0_GPIO_PARK_NONE : STM32L0_GPIO_PARK_HIZ) |
+                                       (STM32L0_GPIO_PUPD_PULLDOWN | STM32L0_GPIO_OSPEED_LOW | STM32L0_GPIO_OTYPE_PUSHPULL | STM32L0_GPIO_MODE_INPUT));
+
+            stm32l0_exti_attach(usbd_pin_vbus,
+                                ((usbd_wakeup ? 0 : STM32L0_EXTI_CONTROL_NOWAKEUP) |
+                                 (STM32L0_EXTI_CONTROL_PRIORITY_LOW | STM32L0_EXTI_CONTROL_EDGE_RISING | STM32L0_EXTI_CONTROL_EDGE_FALLING)),
+                                (stm32l0_exti_callback_t)USBD_VBUSChangedIrq, NULL);
+        }
     }
 }