diff --git a/include/arch/i386/include/vm.h b/include/arch/i386/include/vm.h
index 757a14a8e..71104e0a2 100644
--- a/include/arch/i386/include/vm.h
+++ b/include/arch/i386/include/vm.h
@@ -10,6 +10,7 @@ i386/vm.h
 /* i386 paging constants */
 #define I386_VM_PRESENT	0x001	/* Page is present */
 #define I386_VM_WRITE	0x002	/* Read/write access allowed */
+#define I386_VM_READ	0x000	/* Read access only */
 #define I386_VM_USER	0x004	/* User access allowed */
 #define I386_VM_PWT	0x008	/* Write through */
 #define I386_VM_PCD	0x010	/* Cache disable */
diff --git a/servers/vm/arch/i386/pagetable.h b/servers/vm/arch/i386/pagetable.h
index 68d54c20c..acb12a02a 100644
--- a/servers/vm/arch/i386/pagetable.h
+++ b/servers/vm/arch/i386/pagetable.h
@@ -26,6 +26,7 @@ typedef struct {
 
 /* Mapping flags. */
 #define PTF_WRITE	I386_VM_WRITE
+#define PTF_READ	I386_VM_READ
 #define PTF_PRESENT	I386_VM_PRESENT
 #define PTF_USER	I386_VM_USER
 #define PTF_GLOBAL	I386_VM_GLOBAL
@@ -35,7 +36,7 @@ typedef struct {
 /* For arch-specific PT routines to check if no bits outside
  * the regular flags are set.
  */
-#define PTF_ALLFLAGS	(PTF_WRITE|PTF_PRESENT|PTF_USER|PTF_GLOBAL|PTF_NOCACHE)
+#define PTF_ALLFLAGS   (PTF_READ|PTF_WRITE|PTF_PRESENT|PTF_USER|PTF_GLOBAL|PTF_NOCACHE)
 
 #if SANITYCHECKS
 #define PT_SANE(p) { pt_sanitycheck((p), __FILE__, __LINE__); }
diff --git a/servers/vm/region.c b/servers/vm/region.c
index a7edf1464..857b498db 100644
--- a/servers/vm/region.c
+++ b/servers/vm/region.c
@@ -196,7 +196,7 @@ static int map_sanitycheck_pt(struct vmproc *vmp,
 	if(WRITABLE(vr, pb))
 		rw = PTF_WRITE;
 	else
-		rw = 0;
+		rw = PTF_READ;
 
 	r = pt_writemap(vmp, &vmp->vm_pt, vr->vaddr + pr->offset,
 	  pb->phys, pb->length, PTF_PRESENT | PTF_USER | rw, WMF_VERIFY);
@@ -375,7 +375,7 @@ static int map_ph_writept(struct vmproc *vmp, struct vir_region *vr,
 	if(WRITABLE(vr, pb))
 		rw = PTF_WRITE;
 	else
-		rw = 0;
+		rw = PTF_READ;
 
 	if(pt_writemap(vmp, &vmp->vm_pt, vr->vaddr + pr->offset,
 	  pb->phys, pb->length, PTF_PRESENT | PTF_USER | rw,
@@ -2112,6 +2112,8 @@ static int do_map_memory(struct vmproc *vms, struct vmproc *vmd,
          */
         if(flag > 0)
                 pt_flag |= PTF_WRITE;
+	else
+                pt_flag |= PTF_READ;
 
         /* Map phys blocks in the source process to the destination process. */
         end = offset_d + length;