diff --git a/makefiles/bindist.inc.mk b/makefiles/bindist.inc.mk
index be5f13b496fea4a74070f9a0bd1d2fc0bc3425a5..783edc9ca7c5cdf8d3f119457a1838dac6477ab9 100644
--- a/makefiles/bindist.inc.mk
+++ b/makefiles/bindist.inc.mk
@@ -5,9 +5,9 @@ DIST_FILES += $(BIN_USEMODULE:%=bin/$(BOARD)/%.a)
 # if the file Makefile.distcheck exists, we're executing from within a folder
 # generated by "make bindist".
 ifneq (, $(wildcard Makefile.distcheck))
-	include Makefile.distcheck
+  include Makefile.distcheck
 else
-	DIRS+=$(BIN_DIRS)
+  DIRS+=$(BIN_DIRS)
 endif
 
 bindist: all
diff --git a/makefiles/tools/bossa.inc.mk b/makefiles/tools/bossa.inc.mk
index 4951e38561019f0e6c1f8d99228747a395d44d7c..1ded05c7ac2d2ae7955c56c7764d576424e7f025 100644
--- a/makefiles/tools/bossa.inc.mk
+++ b/makefiles/tools/bossa.inc.mk
@@ -7,20 +7,20 @@ export HEXFILE = $(ELFFILE:.elf=.bin)
 # some arduino boards need to toggle the serial interface a little bit to get
 # them ready for flashing...
 ifneq (,$(BOSSA_ARDUINO_PREFLASH))
-OS := $(shell uname)
-ifeq ($(OS),Linux)
-  STTY_FLAG = -F
-else ifeq ($(OS),Darwin)
-  STTY_FLAG = -f
-endif
+  OS := $(shell uname)
+  ifeq ($(OS),Linux)
+    STTY_FLAG = -F
+  else ifeq ($(OS),Darwin)
+    STTY_FLAG = -f
+  endif
 
-PREFLASHER ?= stty
-PREFFLAGS  ?= $(STTY_FLAG) $(PORT) raw ispeed 1200 ospeed 1200 cs8 -cstopb ignpar eol 255 eof 255
-FLASHDEPS += preflash
+  PREFLASHER ?= stty
+  PREFFLAGS  ?= $(STTY_FLAG) $(PORT) raw ispeed 1200 ospeed 1200 cs8 -cstopb ignpar eol 255 eof 255
+  FLASHDEPS += preflash
 endif
 
 # if we go with the default (BOSSA shipped with RIOT), we download and build
 # the tool if not already done
 ifeq ($(RIOTBASE)/dist/tools/bossa/bossac,$(FLASHER))
-FLASHDEPS += $(RIOTBASE)/dist/tools/bossa/bossac
+  FLASHDEPS += $(RIOTBASE)/dist/tools/bossa/bossac
 endif
diff --git a/makefiles/tools/serial.inc.mk b/makefiles/tools/serial.inc.mk
index af17a2a9c4a6281ee58b36e72817f011ef474161..3144a0ef5501af3e85fab07331838adf0cd2e38d 100644
--- a/makefiles/tools/serial.inc.mk
+++ b/makefiles/tools/serial.inc.mk
@@ -7,7 +7,7 @@ else ifeq ($(OS),Darwin)
 endif
 
 ifeq ($(PORT),)
-    $(info Warning: no PORT set!)
+  $(info Warning: no PORT set!)
 endif
 
 export BAUD ?= 115200