diff --git a/rbutil/mkimxboot/Makefile b/rbutil/mkimxboot/Makefile
index d2c487c475..966423159a 100644
--- a/rbutil/mkimxboot/Makefile
+++ b/rbutil/mkimxboot/Makefile
@@ -13,18 +13,16 @@ COMPILEFLAGS := -Wall -g -O3 -I$(IMXTOOLS_DIR)
 
 # std=gnu99 is required by MinGW on Windows (c99 is sufficient for Linux / MXE)
 CFLAGS += -std=gnu99 $(COMPILEFLAGS)
-CXXFLAGS += $(COMPILEFLAGS)
 
 TOMCRYPT_DIR := ../../utils/tomcrypt
 
-CXXFLAGS += -I$(TOMCRYPT_DIR)/src/headers
 CFLAGS += -I$(TOMCRYPT_DIR)/src/headers
 LDOPTS += -lpthread $(TOMCRYPT_DIR)/librbtomcrypt.a
 
 OUTPUT = mkimxboot
 
 # inputs for lib
-IMXTOOLS_SOURCES = misc.c sb.c crypto.cpp crc.c elf.c
+IMXTOOLS_SOURCES = misc.c sb.c crypto.c crc.c elf.c
 LIBSOURCES := dualboot.c mkimxboot.c md5.c \
 	      $(addprefix $(IMXTOOLS_DIR),$(IMXTOOLS_SOURCES))
 
diff --git a/utils/imxtools/sbtools/Makefile b/utils/imxtools/sbtools/Makefile
index b1d0313f77..64a9651f4a 100644
--- a/utils/imxtools/sbtools/Makefile
+++ b/utils/imxtools/sbtools/Makefile
@@ -15,9 +15,6 @@ all: $(BINS)
 %.o: %.c
 	$(CC) $(CFLAGS) -c -o $@ $<
 
-%.o: %.cpp
-	$(CXX) $(CXXFLAGS) -c -o $@ $<
-
 sbtoelf: sbtoelf.o crc.o crypto.o xorcrypt.o dbparser.o elf.o misc.o sb.o sb1.o $(TOMCRYPT_DIR)/librbtomcrypt.a
 	$(LD) -o $@ $^ $(LDFLAGS)
 
diff --git a/utils/imxtools/sbtools/crypto.cpp b/utils/imxtools/sbtools/crypto.c
similarity index 100%
rename from utils/imxtools/sbtools/crypto.cpp
rename to utils/imxtools/sbtools/crypto.c