diff --git a/Makefile.include b/Makefile.include
index 642a709582..fc08481ce1 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -426,14 +426,15 @@ include $(RIOTMAKE)/boot/riotboot.mk
 elffile: $(ELFFILE)
 hexfile: $(HEXFILE)
 binfile: $(BINFILE)
-# # # FLASHFILE Being introduced, only supported if bsp define FLASHFILE # # #
-# # # Not all boards use this file for the moment
-#
 # FLASHFILE is the file used by the flasher
 # Usually set to $(ELFFILE), $(HEXFILE) or $(BINFILE) in the board/flasher
 # or application specific files
 flashfile: $(FLASHFILE)
 
+ifeq (,$(FLASHFILE))
+  $(error FLASHFILE is not defined for this board: $(FLASHFILE))
+endif
+
 # variables used to compile and link c++
 CPPMIX ?= $(if $(wildcard *.cpp),1,)
 
diff --git a/makefiles/vars.inc.mk b/makefiles/vars.inc.mk
index 206d99a99b..e27e5797fc 100644
--- a/makefiles/vars.inc.mk
+++ b/makefiles/vars.inc.mk
@@ -78,7 +78,7 @@ export PORT                  # The port to connect the TERMPROG to.
 export ELFFILE               # The unstripped result of the compilation.
 export HEXFILE               # The 'intel hex' stripped result of the compilation.
 # BINFILE                    # The 'binary' stripped result of the compilation.
-# FLASHFILE                  # The output file used for flashing (transition phase: only if defined)
+# FLASHFILE                  # The output file used for flashing
 # DEBUGGER                   # The command to call on "make debug", usually a script starting the GDB front-end.
 # DEBUGGER_FLAGS             # The parameters to supply to DEBUGGER.
 # DEBUGSERVER                # The command to call on "make debug-server", usually a script starting the GDB server.