diff --git a/ChangeLog b/ChangeLog
index c0b77d906..f6678af06 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2010-09-13  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	Support explicit user claim that a device is BIOS-visible.
+
+	* grub-core/kern/emu/getroot.c (grub_util_get_dev_abstraction):
+	Return GRUB_DEV_ABSTRACTION_NONE if device is in device.map.
+	* grub-core/kern/emu/hostdisk.c
+	(convert_system_partition_to_system_disk): Support mdX.
+	(find_system_device): New parameter add. All users updated.
+	(grub_util_biosdisk_is_present): New function.
+	* include/grub/emu/hostdisk.h (grub_util_biosdisk_is_present): New
+	proto.
+
 2010-09-13  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Search hints support.
diff --git a/grub-core/kern/emu/getroot.c b/grub-core/kern/emu/getroot.c
index c0a10d22b..32dcb49ca 100644
--- a/grub-core/kern/emu/getroot.c
+++ b/grub-core/kern/emu/getroot.c
@@ -572,6 +572,10 @@ int
 grub_util_get_dev_abstraction (const char *os_dev __attribute__((unused)))
 {
 #ifdef __linux__
+  /* User explicitly claims that this drive is visible by BIOS.  */
+  if (grub_util_biosdisk_is_present (os_dev))
+    return GRUB_DEV_ABSTRACTION_NONE;
+
   /* Check for LVM.  */
   if (!strncmp (os_dev, "/dev/mapper/", 12)
       && ! grub_util_is_dmraid (os_dev)
diff --git a/grub-core/kern/emu/hostdisk.c b/grub-core/kern/emu/hostdisk.c
index 2cdf449e2..1eb6cb9d8 100644
--- a/grub-core/kern/emu/hostdisk.c
+++ b/grub-core/kern/emu/hostdisk.c
@@ -1117,6 +1117,16 @@ convert_system_partition_to_system_disk (const char *os_dev, struct stat *st)
 	  return path;
 	}
 
+      if (strncmp ("md", p, 2) == 0
+	  && p[2] >= '0' && p[2] <= '9')
+	{
+	  char *ptr = p + 2;
+	  while (*ptr >= '0' && *ptr <= '9')
+	    ptr++;
+	  *ptr = 0;
+	  return path;
+	}
+
       /* If this is an IDE, SCSI or Virtio disk.  */
       if (strncmp ("vdisk", p, 5) == 0
 	  && p[5] >= 'a' && p[5] <= 'z')
@@ -1334,7 +1344,7 @@ device_is_wholedisk (const char *os_dev)
 #endif /* defined(__NetBSD__) */
 
 static int
-find_system_device (const char *os_dev, struct stat *st)
+find_system_device (const char *os_dev, struct stat *st, int add)
 {
   unsigned int i;
   char *os_disk;
@@ -1352,6 +1362,9 @@ find_system_device (const char *os_dev, struct stat *st)
 	return i;
       }
 
+  if (!add)
+    return -1;
+
   if (i == ARRAY_SIZE (map))
     grub_util_error (_("device count exceeds limit"));
 
@@ -1361,6 +1374,17 @@ find_system_device (const char *os_dev, struct stat *st)
   return i;
 }
 
+int
+grub_util_biosdisk_is_present (const char *os_dev)
+{
+  struct stat st;
+
+  if (stat (os_dev, &st) < 0)
+    return 0;
+
+  return find_system_device (os_dev, &st, 0) != -1;
+}
+
 char *
 grub_util_biosdisk_get_grub_dev (const char *os_dev)
 {
@@ -1373,7 +1397,7 @@ grub_util_biosdisk_get_grub_dev (const char *os_dev)
       return 0;
     }
 
-  drive = find_system_device (os_dev, &st);
+  drive = find_system_device (os_dev, &st, 1);
   if (drive < 0)
     {
       grub_error (GRUB_ERR_UNKNOWN_DEVICE,
diff --git a/include/grub/emu/hostdisk.h b/include/grub/emu/hostdisk.h
index 246046ee0..5873aa440 100644
--- a/include/grub/emu/hostdisk.h
+++ b/include/grub/emu/hostdisk.h
@@ -26,5 +26,6 @@ void grub_util_biosdisk_init (const char *dev_map);
 void grub_util_biosdisk_fini (void);
 char *grub_util_biosdisk_get_grub_dev (const char *os_dev);
 const char *grub_util_biosdisk_get_osdev (grub_disk_t disk);
+int grub_util_biosdisk_is_present (const char *name);
 
 #endif /* ! GRUB_BIOSDISK_MACHINE_UTIL_HEADER */