diff --git a/labcodes/lab1/Makefile b/labcodes/lab1/Makefile
index 274bb69..eacc043 100644
--- a/labcodes/lab1/Makefile
+++ b/labcodes/lab1/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
diff --git a/labcodes/lab2/Makefile b/labcodes/lab2/Makefile
index f63fc86..c7dc43d 100644
--- a/labcodes/lab2/Makefile
+++ b/labcodes/lab2/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
diff --git a/labcodes/lab3/Makefile b/labcodes/lab3/Makefile
index 52af7f6..bdc49e6 100644
--- a/labcodes/lab3/Makefile
+++ b/labcodes/lab3/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
diff --git a/labcodes/lab4/Makefile b/labcodes/lab4/Makefile
index 6cde461..74cc61d 100644
--- a/labcodes/lab4/Makefile
+++ b/labcodes/lab4/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
diff --git a/labcodes/lab5/Makefile b/labcodes/lab5/Makefile
index d7ce1ca..0ebae6d 100644
--- a/labcodes/lab5/Makefile
+++ b/labcodes/lab5/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
diff --git a/labcodes/lab6/Makefile b/labcodes/lab6/Makefile
index 01701bb..e87d265 100644
--- a/labcodes/lab6/Makefile
+++ b/labcodes/lab6/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
diff --git a/labcodes/lab7/Makefile b/labcodes/lab7/Makefile
index d905d04..b1a879b 100644
--- a/labcodes/lab7/Makefile
+++ b/labcodes/lab7/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
diff --git a/labcodes/lab8/Makefile b/labcodes/lab8/Makefile
index 7c8978e..1125da0 100644
--- a/labcodes/lab8/Makefile
+++ b/labcodes/lab8/Makefile
@@ -53,7 +53,7 @@ CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 &
 else
 HOSTCC		:= clang
 HOSTCFLAGS	:= -g -Wall -O2
-CC		:= $(GCCPREFIX)clang
+CC		:= clang
 CFLAGS	:= -fno-builtin -Wall -g -m32 -mno-sse -nostdinc $(DEFS)
 CFLAGS	+= $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 endif
@@ -369,7 +369,7 @@ print-%:
 .PHONY: clean dist-clean handin packall tags
 clean:
 	$(V)$(RM) $(GRADE_GDB_IN) $(GRADE_QEMU_OUT)  $(SFSBINS) cscope* tags
-	-$(RM) -r $(OBJDIR) $(BINDIR)
+	$(V)$(RM) -r $(OBJDIR) $(BINDIR) $(SFSROOT)
 
 dist-clean: clean
 	-$(RM) $(HANDIN)