diff --git a/boards/common/stm32f103c8/Makefile.include b/boards/common/stm32f103c8/Makefile.include
index da91db4ef7..9862d252c8 100644
--- a/boards/common/stm32f103c8/Makefile.include
+++ b/boards/common/stm32f103c8/Makefile.include
@@ -27,10 +27,10 @@ ifeq ($(PROGRAMMER),dfu-util)
   DEBUGGER = # no debugger
   RESET ?= # dfu-util has no support for resetting the device
 
-  HEXFILE = $(BINFILE)
-  FFLAGS = -d 1eaf:0003 -a 2 -D "$(HEXFILE)"
+  FLASHFILE ?= $(BINFILE)
+  FFLAGS = -d 1eaf:0003 -a 2 -D $(FLASHFILE)
   # for older bootloader versions use this:
-  # FFLAGS = -d 1d50:6017 -s 0x08002000:leave -D "$(HEXFILE)"
+  # FFLAGS = -d 1d50:6017 -s 0x08002000:leave -D $(FLASHFILE)
 else
 
   # this board uses openocd by default
diff --git a/boards/nz32-sc151/Makefile.include b/boards/nz32-sc151/Makefile.include
index 3a5afa200d..e5e377cbea 100644
--- a/boards/nz32-sc151/Makefile.include
+++ b/boards/nz32-sc151/Makefile.include
@@ -13,8 +13,8 @@ FLASHER = dfu-util
 DEBUGGER = # dfu-util has no debugger
 RESET ?= # dfu-util has no support for resetting the device
 
-HEXFILE = $(BINFILE)
-FFLAGS = -d $(ID) -a 0 -s 0x08000000:leave -D "$(HEXFILE)"
+FLASHFILE ?= $(BINFILE)
+FFLAGS = -d $(ID) -a 0 -s 0x08000000:leave -D $(FLASHFILE)
 
 # setup serial terminal
 include $(RIOTMAKE)/tools/serial.inc.mk
diff --git a/boards/spark-core/Makefile.include b/boards/spark-core/Makefile.include
index d81284c9a0..08e80c01a8 100644
--- a/boards/spark-core/Makefile.include
+++ b/boards/spark-core/Makefile.include
@@ -11,8 +11,8 @@ FLASHER = dfu-util
 DEBUGGER = # spark core has no debugger
 RESET ?= # dfu-util has no support for resetting the device
 
-HEXFILE = $(BINFILE)
-FFLAGS = -d 1d50:607f -a 0 -s 0x08005000:leave -D "$(HEXFILE)"
+FLASHFILE ?= $(BINFILE)
+FFLAGS = -d 1d50:607f -a 0 -s 0x08005000:leave -D $(FLASHFILE)
 
 # Skip the space needed by the embedded bootloader
 export ROM_OFFSET ?= 0x5000