diff --git a/Makefile b/Makefile
index 59c75d6..9d8bb78 100644
--- a/Makefile
+++ b/Makefile
@@ -829,7 +829,7 @@
 
 all: hwlibs features $(PROGRAM)$(EXEC_SUFFIX) $(PROGRAM).8
 ifeq ($(ARCH), x86)
-	@+$(MAKE) -C util/ich_descriptors_tool/ TARGET_OS=$(TARGET_OS) EXEC_SUFFIX=$(EXEC_SUFFIX)
+	@+$(MAKE) -C util/ich_descriptors_tool/ HOST_OS=$(HOST_OS) TARGET_OS=$(TARGET_OS)
 endif
 
 $(PROGRAM)$(EXEC_SUFFIX): $(OBJS)
diff --git a/util/ich_descriptors_tool/Makefile b/util/ich_descriptors_tool/Makefile
index a84894e..ea80dc6 100644
--- a/util/ich_descriptors_tool/Makefile
+++ b/util/ich_descriptors_tool/Makefile
@@ -18,20 +18,19 @@
 
 SRC = $(wildcard *.c)
 
-CC ?= gcc
-
 # If the user has specified custom CFLAGS, all CFLAGS settings below will be
 # completely ignored by gnumake.
 CFLAGS ?= -Os -Wall -Wshadow
 
+# Auto determine HOST_OS and TARGET_OS if they are not set as argument
 HOST_OS ?= $(shell uname)
+TARGET_OS := $(call c_macro_test, ../../Makefile.d/os_test.h)
+
 ifeq ($(findstring MINGW, $(HOST_OS)), MINGW)
 # Explicitly set CC = gcc on MinGW, otherwise: "cc: command not found".
 CC = gcc
 endif
 
-override TARGET_OS := $(call c_macro_test, ../../Makefile.d/os_test.h)
-
 ifeq ($(TARGET_OS), DOS)
 EXEC_SUFFIX := .exe
 # DJGPP has odd uint*_t definitions which cause lots of format string warnings.
@@ -41,7 +40,7 @@
 ifeq ($(TARGET_OS), MinGW)
 EXEC_SUFFIX := .exe
 # Some functions provided by Microsoft do not work as described in C99 specifications. This macro fixes that
-# for MinGW. See http://sourceforge.net/p/mingw-w64/wiki2/printf%20and%20scanf%20family/ */
+# for MinGW. See http://sourceforge.net/p/mingw-w64/wiki2/printf%20and%20scanf%20family/
 FLASHROM_CFLAGS += -D__USE_MINGW_ANSI_STDIO=1
 endif
 
@@ -72,6 +71,7 @@
 $(PROGRAM)$(EXEC_SUFFIX): $(OBJ) $(SHAREDOBJ)
 	$(CC) $(LDFLAGS) -o $(PROGRAM)$(EXEC_SUFFIX) $(OBJ) $(SHAREDOBJ)
 
+# We don't use EXEC_SUFFIX here because we want to clean everything.
 clean:
 	rm -f $(PROGRAM) $(PROGRAM).exe
 	rm -rf $(DEPPATH) $(OBJATH)