* grub-core/partmap/amiga.c (GRUB_AMIGA_PART_MAGIC): New define.

(amiga_partition_map_iterate): Check "PART" magic to avoid a very long
	loop in case of incorrect amiga partmap.

grub-core/partmap/amiga.c

@@ -44,6 +44,7 @@ struct grub_amiga_partition
 {
   /* "PART".  */
   grub_uint8_t magic[4];
+#define GRUB_AMIGA_PART_MAGIC "PART"
   grub_int32_t size;
   grub_int32_t checksum;
   grub_uint32_t scsihost;
@@ -110,6 +111,9 @@ amiga_partition_map_iterate (grub_disk_t disk,
       if (grub_disk_read (disk, next, 0, sizeof (apart), &apart))
 	return grub_errno;
 
+      if (grub_memcmp (apart.magic, GRUB_AMIGA_PART_MAGIC,
+		       sizeof (apart.magic)) == 0)
+
       /* Calculate the first block and the size of the partition.  */
       part.start = (grub_be_to_cpu32 (apart.lowcyl)
 		    * grub_be_to_cpu32 (apart.heads)