diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk
index d0145a90f3..5df48debeb 100644
--- a/py/circuitpy_mpconfig.mk
+++ b/py/circuitpy_mpconfig.mk
@@ -100,7 +100,7 @@ CFLAGS += -DCIRCUITPY_BLEIO=$(CIRCUITPY_BLEIO)
 CIRCUITPY_BOARD ?= 1
 CFLAGS += -DCIRCUITPY_BOARD=$(CIRCUITPY_BOARD)
 
-CIRCUITPY_BUSDEVICE = 0
+CIRCUITPY_BUSDEVICE ?= $(CIRCUITPY_FULL_BUILD)
 CFLAGS += -DCIRCUITPY_BUSDEVICE=$(CIRCUITPY_BUSDEVICE)
 
 CIRCUITPY_BUILTINS_POW3 ?= $(CIRCUITPY_FULL_BUILD)