diff --git a/ChangeLog b/ChangeLog
index ea293f27a..1a57fff20 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2008-01-22  Robert Millan  <rmh@aybabtu.com>
+
+	* disk/ieee1275/ofdisk.c (grub_ofdisk_iterate): When
+	`GRUB_IEEE1275_FLAG_OFDISK_SDCARD_ONLY' flag is set, skip any
+	device that doesn't look like an SD card.
+	* include/grub/ieee1275/ieee1275.h (grub_ieee1275_flag): Add
+	`GRUB_IEEE1275_FLAG_OFDISK_SDCARD_ONLY' flag.
+	* kern/powerpc/ieee1275/cmain.c (grub_ieee1275_set_flag): Detect
+	OLPC laptop, and set `GRUB_IEEE1275_FLAG_OFDISK_SDCARD_ONLY' when
+	found.
+
 2008-01-22  Robert Millan  <rmh@aybabtu.com>
 
 	* kern/powerpc/ieee1275/init.c (grub_claim_heap): Add sanity check to
diff --git a/disk/ieee1275/ofdisk.c b/disk/ieee1275/ofdisk.c
index e1b31b6d0..d86d95327 100644
--- a/disk/ieee1275/ofdisk.c
+++ b/disk/ieee1275/ofdisk.c
@@ -30,6 +30,33 @@ grub_ofdisk_iterate (int (*hook) (const char *name))
 
   int dev_iterate (struct grub_ieee1275_devalias *alias)
     {
+      grub_dprintf ("disk", "disk name = %s\n", alias->name);
+
+      if (grub_ieee1275_test_flag (GRUB_IEEE1275_FLAG_OFDISK_SDCARD_ONLY))
+	{
+	  grub_ieee1275_phandle_t dev;
+	  char tmp[8];
+
+	  if (grub_ieee1275_finddevice (alias->path, &dev))
+	    {
+	      grub_dprintf ("disk", "finddevice (%s) failed\n", alias->path);
+	      return 0;
+	    }
+
+	  if (grub_ieee1275_get_property (dev, "iconname", tmp,
+					  sizeof tmp, 0))
+	    {
+	      grub_dprintf ("disk", "get iconname failed\n");
+	      return 0;
+	    }
+
+	  if (grub_strcmp (tmp, "sdmmc"))
+	    {
+	      grub_dprintf ("disk", "device is not an SD card\n");
+	      return 0;
+	    }
+	}
+
       if (! grub_strcmp (alias->type, "block"))
 	hook (alias->name);
       else if ((! grub_strcmp (alias->type, "scsi"))
diff --git a/include/grub/ieee1275/ieee1275.h b/include/grub/ieee1275/ieee1275.h
index e1cf0c4ba..008a114f6 100644
--- a/include/grub/ieee1275/ieee1275.h
+++ b/include/grub/ieee1275/ieee1275.h
@@ -83,6 +83,9 @@ enum grub_ieee1275_flag
 
   /* CodeGen firmware does not correctly implement "output-device output" */
   GRUB_IEEE1275_FLAG_BROKEN_OUTPUT,
+
+  /* OLPC / XO firmware hangs when accessing USB devices.  */
+  GRUB_IEEE1275_FLAG_OFDISK_SDCARD_ONLY,
 };
 
 extern int EXPORT_FUNC(grub_ieee1275_test_flag) (enum grub_ieee1275_flag flag);
diff --git a/kern/powerpc/ieee1275/cmain.c b/kern/powerpc/ieee1275/cmain.c
index 91e22b374..2b7cce56c 100644
--- a/kern/powerpc/ieee1275/cmain.c
+++ b/kern/powerpc/ieee1275/cmain.c
@@ -49,27 +49,35 @@ grub_ieee1275_set_flag (enum grub_ieee1275_flag flag)
 static void
 grub_ieee1275_find_options (void)
 {
+  grub_ieee1275_phandle_t root;
   grub_ieee1275_phandle_t options;
   grub_ieee1275_phandle_t openprom;
   int rc;
   int realmode = 0;
   char tmp[32];
   int is_smartfirmware = 0;
+  int is_olpc = 0;
 
+  grub_ieee1275_finddevice ("/", &root);
   grub_ieee1275_finddevice ("/options", &options);
+  grub_ieee1275_finddevice ("/openprom", &openprom);
+
   rc = grub_ieee1275_get_integer_property (options, "real-mode?", &realmode,
 					   sizeof realmode, 0);
   if (((rc >= 0) && realmode) || (grub_ieee1275_mmu == 0))
     grub_ieee1275_set_flag (GRUB_IEEE1275_FLAG_REAL_MODE);
 
-  grub_ieee1275_finddevice ("/openprom", &openprom);
-
   rc = grub_ieee1275_get_property (openprom, "CodeGen-copyright",
 				   tmp,	sizeof (tmp), 0);
 #define SF "SmartFirmware(tm)"
   if (rc >= 0 && !grub_strncmp (tmp, SF, sizeof (SF) - 1))
     is_smartfirmware = 1;
 
+  rc = grub_ieee1275_get_property (root, "architecture",
+				   tmp,	sizeof (tmp), 0);
+  if (rc >= 0 && !grub_strcmp (tmp, "OLPC"))
+    is_olpc = 1;
+
   if (is_smartfirmware)
     {
       /* Broken in all versions */
@@ -101,6 +109,30 @@ grub_ieee1275_find_options (void)
 	    }
 	}
     }
+
+  if (is_olpc)
+    {
+      /* OLPC / XO laptops have three kinds of storage devices:
+
+	 - NAND flash.  These are accessible via OFW callbacks, but:
+	   - Follow strange semantics, imposed by hardware constraints.
+	   - Its ABI is undocumented, and not stable.
+	   They lack "device_type" property, which conveniently makes GRUB
+	   skip them.
+
+	 - USB drives.  Not accessible, because OFW shuts down the controller
+	   in order to prevent collisions with applications accessing it
+	   directly.  Even worse, attempts to access it will NOT return
+	   control to the caller, so we have to avoid probing them.
+
+	 - SD cards.  These work fine.
+
+	 To avoid brekage, we only need to skip USB probing.  However,
+	 since detecting SD cards is more reliable, we do that instead.
+      */
+
+      grub_ieee1275_set_flag (GRUB_IEEE1275_FLAG_OFDISK_SDCARD_ONLY);
+    }
 }
 
 void cmain (void);