diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 11f6bb153d..2c699f5da6 100644
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -334,7 +334,7 @@ dfu-bootloader:
 
 uf2: $(BUILD)/$(OUTPUT_FILENAME).hex
 	$(ECHO) "Create $(OUTPUT_FILENAME).uf2"
-	$(PYTHON2) $(TOP)/tools/uf2/utils/uf2conv.py -c -o "$(BUILD)/$(OUTPUT_FILENAME).uf2" $^
+	$(PYTHON2) $(TOP)/tools/uf2/utils/uf2conv.py -f 0xADA52840 -c -o "$(BUILD)/$(OUTPUT_FILENAME).uf2" $^
 
 
 
diff --git a/ports/nrf/boards/feather52840/mpconfigboard.mk b/ports/nrf/boards/feather52840/mpconfigboard.mk
index 598f73631c..869724d4d8 100644
--- a/ports/nrf/boards/feather52840/mpconfigboard.mk
+++ b/ports/nrf/boards/feather52840/mpconfigboard.mk
@@ -5,9 +5,13 @@ SD ?= s140
 SOFTDEV_VERSION ?= 6.0.0
 
 BOOT_SETTING_ADDR = 0xFF000
-
-LD_FILE = boards/bluefruit_$(MCU_SUB_VARIANT)_$(SD_LOWER)_$(SOFTDEV_VERSION).ld
 BOOT_FILE = boards/$(BOARD)/bootloader/$(SOFTDEV_VERSION)/$(BOARD)_bootloader_$(SOFTDEV_VERSION)_s140
 
+ifeq ($(SD),)
+	LD_FILE = boards/nrf52840_1M_256k.ld
+else
+	LD_FILE = boards/bluefruit_$(MCU_SUB_VARIANT)_$(SD_LOWER)_$(SOFTDEV_VERSION).ld
+endif
+
 NRF_DEFINES += -DNRF52840_XXAA
 NRF_DEFINES += -DADAFRUIT_FEATHER52840
diff --git a/ports/nrf/boards/pca10056/mpconfigboard.mk b/ports/nrf/boards/pca10056/mpconfigboard.mk
index 598f73631c..9db7a815ee 100644
--- a/ports/nrf/boards/pca10056/mpconfigboard.mk
+++ b/ports/nrf/boards/pca10056/mpconfigboard.mk
@@ -5,9 +5,14 @@ SD ?= s140
 SOFTDEV_VERSION ?= 6.0.0
 
 BOOT_SETTING_ADDR = 0xFF000
-
-LD_FILE = boards/bluefruit_$(MCU_SUB_VARIANT)_$(SD_LOWER)_$(SOFTDEV_VERSION).ld
 BOOT_FILE = boards/$(BOARD)/bootloader/$(SOFTDEV_VERSION)/$(BOARD)_bootloader_$(SOFTDEV_VERSION)_s140
 
+ifeq ($(SD),)
+	LD_FILE = boards/nrf52840_1M_256k.ld
+else
+	LD_FILE = boards/bluefruit_$(MCU_SUB_VARIANT)_$(SD_LOWER)_$(SOFTDEV_VERSION).ld
+endif
+
+
 NRF_DEFINES += -DNRF52840_XXAA
 NRF_DEFINES += -DADAFRUIT_FEATHER52840