diff --git a/drivers/SAMD21/grblHAL_MKRZERO/src/usb_serial.cpp b/drivers/SAMD21/grblHAL_MKRZERO/src/usb_serial.cpp
index a50550cd..09940a6c 100644
--- a/drivers/SAMD21/grblHAL_MKRZERO/src/usb_serial.cpp
+++ b/drivers/SAMD21/grblHAL_MKRZERO/src/usb_serial.cpp
@@ -121,11 +121,11 @@ void usb_serialWriteS (const char *s)
 
             while(txbuf.length) {
 
-                if((avail = Serial.availableForWrite()) > 10) {
+                if((avail = SerialUSB.availableForWrite()) > 10) {
 
                     length = avail < txbuf.length ? avail : txbuf.length;
 
-                    Serial.write((uint8_t *)txbuf.s, length); // doc is wrong - does not return bytes sent!
+                    SerialUSB.write((uint8_t *)txbuf.s, length); // doc is wrong - does not return bytes sent!
 
                     txbuf.length -= length;
                     txbuf.s += length;
diff --git a/drivers/STM32F4xx/Src/driver.c b/drivers/STM32F4xx/Src/driver.c
index f5833c32..eb6af179 100644
--- a/drivers/STM32F4xx/Src/driver.c
+++ b/drivers/STM32F4xx/Src/driver.c
@@ -1374,6 +1374,8 @@ bool driver_init (void)
     hal.info = "STM32F446";
 #elif defined(STM32F411xE)
     hal.info = "STM32F411";
+#elif defined(STM32F407xx)
+    hal.info = "STM32F407";
 #else
     hal.info = "STM32F401CC";
 #endif