diff --git a/hardware/arduino/avr/cores/arduino/USBCore.cpp b/hardware/arduino/avr/cores/arduino/USBCore.cpp
index c46c75fe9..2c03e5a9a 100644
--- a/hardware/arduino/avr/cores/arduino/USBCore.cpp
+++ b/hardware/arduino/avr/cores/arduino/USBCore.cpp
@@ -57,12 +57,18 @@ const u16 STRING_LANGUAGE[2] = {
 const u8 STRING_PRODUCT[] PROGMEM = USB_PRODUCT;
 
 #if USB_VID == 0x2341
-#define USB_MANUFACTURER "Arduino LLC"
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "Arduino LLC"
 #elif USB_VID == 0x1b4f
-#define USB_MANUFACTURER "SparkFun"
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "SparkFun"
 #elif !defined(USB_MANUFACTURER)
 // Fall through to unknown if no manufacturer name was provided in a macro
-#define USB_MANUFACTURER "Unknown"
+#  define USB_MANUFACTURER "Unknown"
 #endif
 
 const u8 STRING_MANUFACTURER[] PROGMEM = USB_MANUFACTURER;
diff --git a/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp b/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp
index b086e5080..c21fda7f4 100644
--- a/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp
+++ b/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp
@@ -69,10 +69,13 @@ const uint16_t STRING_LANGUAGE[2] = {
 const uint8_t STRING_PRODUCT[] = USB_PRODUCT;
 
 #if USB_VID == 0x2341
-#define USB_MANUFACTURER "Arduino LLC"
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "Arduino LLC"
 #elif !defined(USB_MANUFACTURER)
 // Fall through to unknown if no manufacturer name was provided in a macro
-#define USB_MANUFACTURER "Unknown"
+#  define USB_MANUFACTURER "Unknown"
 #endif
 
 const uint8_t STRING_MANUFACTURER[12] = USB_MANUFACTURER;