diff --git a/ports/nrf/boards/pca10100/mpconfigboard.mk b/ports/nrf/boards/pca10100/mpconfigboard.mk
index 6381df74f4..c487753fa7 100644
--- a/ports/nrf/boards/pca10100/mpconfigboard.mk
+++ b/ports/nrf/boards/pca10100/mpconfigboard.mk
@@ -26,6 +26,7 @@ CIRCUITPY_PIXELBUF  = 0
 CIRCUITPY_RE = 0
 CIRCUITPY_RGBMATRIX = 0
 CIRCUITPY_SDCARDIO = 0
+CIRCUITPY_SYNTHIO = 0
 CIRCUITPY_ULAB = 0
 CIRCUITPY_USB_MIDI = 0