diff --git a/drivers/misc/dev_mem.c b/drivers/misc/dev_mem.c
index c78eaa5f511..a6cf1ec2f63 100644
--- a/drivers/misc/dev_mem.c
+++ b/drivers/misc/dev_mem.c
@@ -29,22 +29,15 @@
 #include <sys/mman.h>
 
 /****************************************************************************
- * Pre-processor Definitions
+ * Private Data
  ****************************************************************************/
 
-#define DEVMEM_REGION 8
-
 #ifdef CONFIG_BOARD_MEMORY_RANGE
 static const struct memory_region_s g_memory_region[] =
   {
     CONFIG_BOARD_MEMORY_RANGE
   };
-#endif
-
-/****************************************************************************
- * Public Data
- ****************************************************************************/
-
+#else
 extern uint8_t _stext[];           /* Start of .text */
 extern uint8_t _etext[];           /* End_1 of .text + .rodata */
 extern uint8_t _sdata[];           /* Start of .data */
@@ -52,6 +45,15 @@ extern uint8_t _edata[];           /* End+1 of .data */
 extern uint8_t _sbss[];            /* Start of .bss */
 extern uint8_t _ebss[];            /* End+1 of .bss */
 
+static const struct memory_region_s g_memory_region[] =
+  {
+    { (uintptr_t)_stext, (uintptr_t)_etext, PROT_EXEC | PROT_READ },
+    { (uintptr_t)_sdata, (uintptr_t)_edata, PROT_WRITE | PROT_READ },
+    { (uintptr_t)_sbss,  (uintptr_t)_ebss,  PROT_WRITE | PROT_READ },
+    { 0, 0, 0 },
+  };
+#endif
+
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
@@ -98,15 +100,8 @@ static ssize_t devmem_read(FAR struct file *filep, FAR char *buffer,
   ssize_t len;
   int i;
 
-  DEBUGASSERT(region && src);
-
-  for (i = 0; i < DEVMEM_REGION; i++)
+  for (i = 0; region[i].start != 0 && region[i].end != 0; i++)
     {
-      if (region[i].start == 0 && region[i].end == 0)
-        {
-          break;
-        }
-
       start = MAX(src, region[i].start);
       end = MIN(start + buflen, region[i].end);
       len = end - start;
@@ -135,15 +130,8 @@ static ssize_t devmem_write(FAR struct file *filep, FAR const char *buffer,
   ssize_t len;
   int i;
 
-  DEBUGASSERT(region && dest);
-
-  for (i = 0; i < DEVMEM_REGION; i++)
+  for (i = 0; region[i].start != 0 && region[i].end != 0; i++)
     {
-      if (region[i].start == 0 && region[i].end == 0)
-        {
-          break;
-        }
-
       start = MAX(dest, region[i].start);
       end = MIN(start + buflen, region[i].end);
       len = end - start;
@@ -170,8 +158,6 @@ static int devmem_mmap(FAR struct file *filep,
   uintptr_t end;
   int i;
 
-  DEBUGASSERT(region);
-
   if (map->offset < 0)
     {
       return -EINVAL;
@@ -180,13 +166,8 @@ static int devmem_mmap(FAR struct file *filep,
   start = map->offset;
   end = start + map->length;
 
-  for (i = 0; i < DEVMEM_REGION; i++)
+  for (i = 0; region[i].start != 0 && region[i].end != 0; i++)
     {
-      if (region[i].start == 0 && region[i].end == 0)
-        {
-          break;
-        }
-
       if (start >= region[i].start && end <= region[i].end)
         {
           map->vaddr = (FAR void *)start;
@@ -214,53 +195,6 @@ static int devmem_mmap(FAR struct file *filep,
 
 int devmem_register(void)
 {
-  FAR struct memory_region_s *region;
-  int ret;
-
-#ifndef CONFIG_BOARD_MEMORY_RANGE
-  bool merge = (&_edata[0] == &_sbss[0]);
-  ssize_t len = 0;
-  region = kmm_calloc(DEVMEM_REGION, sizeof(*region));
-  if (region == NULL)
-    {
-      return -ENOMEM;
-    }
-
-  if (len + (4 - merge) > DEVMEM_REGION)
-    {
-      len = DEVMEM_REGION - (4 - merge);
-    }
-
-    region[len].flags = PROT_EXEC | PROT_READ;
-    region[len].start = (uintptr_t)_stext;
-    region[len++].end = (uintptr_t)_etext;
-    region[len].flags = PROT_WRITE | PROT_READ;
-    region[len].start = (uintptr_t)_sdata;
-    region[len++].end = (uintptr_t)_edata;
-
-  if (merge)
-    {
-      region[len - 1].end = (uintptr_t)_ebss;
-    }
-  else
-    {
-      region[len].flags = PROT_WRITE | PROT_READ;
-      region[len].start = (uintptr_t)_sbss;
-      region[len++].end = (uintptr_t)_ebss;
-    }
-#else
-  region = (FAR struct memory_region_s *)g_memory_region;
-#endif
-  /* register the new MEM driver */
-
-  ret = register_driver("/dev/mem", &g_devmem_fops, 0666, region);
-  if (ret < 0)
-    {
-#ifndef CONFIG_BOARD_MEMORY_RANGE
-      kmm_free(region);
-#endif
-      return -ENOMEM;
-    }
-
-  return ret;
+  return register_driver("/dev/mem", &g_devmem_fops,
+                         0666, (FAR void *)g_memory_region);
 }