diff --git a/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.mk b/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.mk
index eea3a27f13..2c8910a66a 100644
--- a/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.mk
+++ b/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.mk
@@ -9,3 +9,5 @@ CHIP_FAMILY = samd21
 INTERNAL_FLASH_FILESYSTEM = 1
 LONGINT_IMPL = NONE
 CIRCUITPY_FULL_BUILD = 0
+
+CIRCUITPY_ONEWIREIO = 0
diff --git a/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.mk b/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.mk
index b8ac2dc256..8d1de11be7 100644
--- a/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.mk
+++ b/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.mk
@@ -9,3 +9,5 @@ CHIP_FAMILY = samd21
 INTERNAL_FLASH_FILESYSTEM = 1
 LONGINT_IMPL = NONE
 CIRCUITPY_FULL_BUILD = 0
+
+CIRCUITPY_ONEWIREIO = 0