diff --git a/src/init/psx_init_cwd.c b/src/init/psx_init_cwd.c

index 924b1b8..02846ba 100644

--- a/src/init/psx_init_cwd.c

+++ b/src/init/psx_init_cwd.c

@@ -17,7 +17,7 @@

 #ifndef __PSX_DEFAULT_ROOT_DIRECTORY

 #define __PSX_DEFAULT_ROOT_DIRECTORY { \

 				'\\','?','?','\\', \

-				'C',':','\\','m','i','d','i','p','i','x'}

+				'Z',':','\\'}

 #endif

 int32_t __psx_init_cwd(void)

diff --git a/project/common.mk b/project/common.mk

index 4390578..fa6df57 100644

--- a/project/common.mk

+++ b/project/common.mk

@@ -102,6 +102,7 @@ COMMON_SRCS = \

 	src/kernel/_systime.c \

 	src/kernel/_uname.c \

 	src/mman/_mmap.c \

+	src/mman/_mprotect.c \

 	src/mman/_mremap.c \

 	src/mman/_munmap.c \

 	src/mount/_mount.c \

diff --git a/src/init/psx_dev_wip.c b/src/init/psx_dev_wip.c

index fe319bc..3915590 100644

--- a/src/init/psx_dev_wip.c

+++ b/src/init/psx_dev_wip.c

@@ -89,6 +89,7 @@ static void __populate_syscall_vtbl(void)

 	/* mman */

 	set_syscall_pointer(mmap);

+	set_syscall_pointer(mprotect);

 	set_syscall_pointer(mremap);

 	set_syscall_pointer(munmap);

@@ -263,6 +264,7 @@ static void __populate_strace_vtbl(void)

 	/* mman */

 	set_strace_pointer(mmap);

+	set_strace_pointer(mprotect);

 	set_strace_pointer(mremap);

 	set_strace_pointer(munmap);

diff --git a/src/internal/psx.h b/src/internal/psx.h

index 1791bda..21efa46 100644

--- a/src/internal/psx.h

+++ b/src/internal/psx.h

@@ -97,6 +97,7 @@ typedef intptr_t	__sys_routine(uname)(struct __utsname *);

 /* mman */

 typedef void *		__sys_routine(mmap)(void * addr, size_t length, int prot, int flags, int,off_t offset);

+typedef intptr_t	__sys_routine(mprotect)(void * addr, size_t length, int prot);

 typedef void *		__sys_routine(mremap)(void * mapaddr, size_t mapsize, size_t newsize, int flags);

 typedef intptr_t	__sys_routine(munmap)(void * addr, size_t length);

@@ -270,6 +271,7 @@ __sys_interface(uname);

 /* mman */

 __sys_interface(mmap);

+__sys_interface(mprotect);

 __sys_interface(mremap);

 __sys_interface(munmap);

diff --git a/src/internal/psx_strace.c b/src/internal/psx_strace.c

index 6d39093..45e7ecd 100644

--- a/src/internal/psx_strace.c

+++ b/src/internal/psx_strace.c

@@ -859,6 +859,22 @@ void * __strace_mmap(void * addr,size_t length,int prot,int flags,int fd,off_t o

 }

+intptr_t __strace_mprotect(void * addr,size_t length,int prot)

+{

+	struct __strace_params params = {

+		__STRACE_MPROTECT,3,

+		{__STRACE_SINTEGER,0},

+		{{__STRACE_POINTER,(intptr_t)addr},

+		 {__STRACE_SINTEGER,length},

+		 {__STRACE_SINTEGER,prot}}};

+

+	if (!addr) params.params[0].type = __STRACE_SINTEGER;

+	params.ret.value = (intptr_t)__sys_mprotect(addr,length,prot);

+	__strace(&params);

+	return (void *)params.ret.value;

+

+}

+

 void * __strace_mremap(void * mapaddr, size_t mapsize, size_t newsize, int flags)

 {

 	struct __strace_params params = {

diff --git a/src/internal/psx_strace.h b/src/internal/psx_strace.h

index 67eecce..293cfdf 100644

--- a/src/internal/psx_strace.h

+++ b/src/internal/psx_strace.h

@@ -60,6 +60,7 @@ enum __strace_sysids {

 	__STRACE_SYSINFO,

 	__STRACE_UNAME,

 	__STRACE_MMAP,

+	__STRACE_MPROTECT,

 	__STRACE_MREMAP,

 	__STRACE_MUNMAP,

 	__STRACE_MOUNT,

@@ -197,6 +198,7 @@ enum __strace_sysids {

 	"sysinfo",			\

 	"uname",			\

 	"mmap",				\

+	"mprotect",			\

 	"mremap",			\

 	"munmap",			\

 	"mount",			\

@@ -346,6 +348,7 @@ __strace_interface(uname);

 /* mman */

 __strace_interface(mmap);

+__strace_interface(mprotect);

 __strace_interface(mremap);

 __strace_interface(munmap);

diff --git a/src/mman/_mmap.c b/src/mman/_mmap.c

index 13762e3..27ea942 100644

--- a/src/mman/_mmap.c

+++ b/src/mman/_mmap.c

@@ -95,7 +95,9 @@ void * __sys_mmap(

 		return (void *)__psx_sig_epilog(m.tlca,-EINVAL,EPSXONLY);

 	/* protection */

-	if (__psx_convert_flags_to_native(

+	if (!prot)

+		m.cprot = NT_PAGE_NOACCESS;

+	else if (__psx_convert_flags_to_native(

 			__mmap_section_prot,

 			prot,&m.cprot,0))

 		return (void *)__psx_sig_epilog(m.tlca,-EINVAL,EPSXONLY);

diff --git a/src/mman/_mprotect.c b/src/mman/_mprotect.c

new file mode 100644

index 0000000..7ac46d3

--- /dev/null

+++ b/src/mman/_mprotect.c

@@ -0,0 +1,61 @@

+/********************************************************/

+/*  psxscl: a thread-safe system call layer library     */

+/*  Copyright (C) 2013--2016  Z. Gilboa                 */

+/*  Released under GPLv2 and GPLv3; see COPYING.PSXSCL. */

+/********************************************************/

+

+#include <ntapi/ntapi.h>

+#include "psx_systypes.h"

+#include "psx_tlca.h"

+#include "psx_errno.h"

+#include "psx_flags.h"

+#include "psx_mman.h"

+#include "psx_signal.h"

+#include "psx_ofd.h"

+#include "psx_acl.h"

+#include "psx.h"

+

+static const struct __flag_set __mmap_section_prot[] = {

+	{PROT_READ,	NT_PAGE_READONLY},

+	{PROT_WRITE,	NT_PAGE_READWRITE},

+	{PROT_EXEC,	NT_PAGE_EXECUTE},

+	{PROT_NONE,	0},

+	{0,		0}};

+

+

+__psx_api

+intptr_t __sys_mprotect(

+	void *	addr,

+	size_t	length,

+	int	prot)

+{

+	int32_t			status;

+	struct __psx_tlca *	tlca;

+	struct __psx_ctx *	ctx;

+	uint32_t		cprot, protect_type_old;

+

+	/* prolog */

+	tlca = __tlca_self();

+	if (!(ctx = __tlca_shared_ctx(tlca))) return 0;

+	__psx_sig_prolog(tlca);

+

+

+	/* protection */

+	if (!prot)

+		cprot = NT_PAGE_NOACCESS;

+	else if (__psx_convert_flags_to_native(

+			__mmap_section_prot,

+			prot,&cprot,0))

+		return __psx_sig_epilog(tlca,-EINVAL,EPSXONLY);

+

+	if (cprot & NT_PAGE_READWRITE)

+		cprot = NT_PAGE_READWRITE;

+

+	if ((status = __ntapi->zw_protect_virtual_memory(

+			NT_CURRENT_PROCESS_HANDLE,

+			&addr, &length,

+			cprot, &protect_type_old)))

+		return __psx_sig_epilog(tlca,-ENOMEM,status);

+

+	return __psx_sig_epilog(tlca,0,status);

+}