diff -ur grub-0.90.orig/stage2/disk_io.c grub-0.90/stage2/disk_io.c
--- grub-0.90.orig/stage2/disk_io.c	Fri Aug 31 10:35:04 2001
+++ grub-0.90/stage2/disk_io.c	Fri Aug 31 10:35:11 2001
@@ -455,31 +455,49 @@
 int
 set_partition_hidden_flag (int hidden)
 {
-  char mbr[512];
-  
-  if (current_drive & 0x80)
-    {
-      int part = current_partition >> 16;
+	unsigned long part = 0xFFFFFF;
+	unsigned long start, len, offset, ext_offset;
+	int entry, type;
+	char mbr[512];
 
-      if (part > 3)
+	/* The drive must be a hard disk.  */
+	if (! (current_drive & 0x80))
 	{
-          errnum = ERR_NO_PART;
-          return 0;
-        }
-
-      if (! rawread (current_drive, 0, 0, SECTOR_SIZE, mbr))
-        return 0;
-
-      if (hidden)
-	PC_SLICE_TYPE (mbr, part) |= PC_SLICE_TYPE_HIDDEN_FLAG;
-      else
-	PC_SLICE_TYPE (mbr, part) &= ~PC_SLICE_TYPE_HIDDEN_FLAG;
-      
-      if (! rawwrite (current_drive, 0, mbr))
-	return 0;
-    }
+		errnum = ERR_BAD_ARGUMENT;
+		return 1;
+	}
 
-  return 1;
+	/* The partition must be a PC slice.  */
+	if ((current_partition >> 16) == 0xFF
+	    || (current_partition & 0xFFFF) != 0xFFFF)
+	{
+		errnum = ERR_BAD_ARGUMENT;
+		return 1;
+	}
+
+	/* Look for the partition.  */
+	while (next_partition (current_drive, 0xFFFFFF, &part, &type,                                          &start, &len, &offset, &entry,
+			       &ext_offset, mbr))
+	{                                                                                       if (part == current_partition)
+		{
+			/* Found.  */
+
+			if (hidden)
+				PC_SLICE_TYPE (mbr, entry) |= PC_SLICE_TYPE_HIDDEN_FLAG;
+			else
+				PC_SLICE_TYPE (mbr, entry) &= ~PC_SLICE_TYPE_HIDDEN_FLAG;       
+
+			/* Write back the MBR to the disk.  */
+			buf_track = -1;
+			if (! rawwrite (current_drive, offset, mbr))
+				return 1;
+
+			/* Succeed.  */
+			return 0;
+		}
+	}
+
+	return 1;
 }