diff --git a/ports/atmel-samd/boards/hallowing_m0_express/board.c b/ports/atmel-samd/boards/hallowing_m0_express/board.c
index ab166d39be..23b1194138 100644
--- a/ports/atmel-samd/boards/hallowing_m0_express/board.c
+++ b/ports/atmel-samd/boards/hallowing_m0_express/board.c
@@ -94,6 +94,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA00);
+    common_hal_displayio_display_set_auto_brightness(display, true);
 }
 
 bool board_requests_safe_mode(void) {
diff --git a/ports/atmel-samd/boards/pyportal/board.c b/ports/atmel-samd/boards/pyportal/board.c
index 3ef079e537..9b05063baf 100644
--- a/ports/atmel-samd/boards/pyportal/board.c
+++ b/ports/atmel-samd/boards/pyportal/board.c
@@ -91,6 +91,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PB31);
+    common_hal_displayio_display_set_auto_brightness(display, true);
 }
 
 bool board_requests_safe_mode(void) {