diff --git a/grub-core/osdep/linux/hostdisk.c b/grub-core/osdep/linux/hostdisk.c
index 06179fca7..8b92f8528 100644
--- a/grub-core/osdep/linux/hostdisk.c
+++ b/grub-core/osdep/linux/hostdisk.c
@@ -374,7 +374,8 @@ grub_util_fd_open_device (const grub_disk_t disk, grub_disk_addr_t sector, int f
     char dev[PATH_MAX];
     grub_disk_addr_t part_start = 0;
 
-    part_start = grub_partition_get_start (disk->partition);
+    part_start = grub_partition_get_start (disk->partition)
+                 >> (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
 
     strncpy (dev, grub_util_biosdisk_get_osdev (disk), sizeof (dev) - 1);
     dev[sizeof(dev) - 1] = '\0';