diff --git a/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.mk b/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.mk
index e427e94301..fd66f425da 100644
--- a/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.mk
+++ b/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.mk
@@ -14,3 +14,6 @@ LONGINT_IMPL = MPZ
 
 CFLAGS_INLINE_LIMIT = 60
 SUPEROPT_GC = 0
+
+CIRCUITPY_I2CSLAVE = 0
+CIRCUITPY_RTC = 0