diff -r 59814c4fed40 -r 21692a51cebb loader/i386/bsd.c
--- a/loader/i386/bsd.c	Thu Feb 18 13:44:25 2010 -0800
+++ b/loader/i386/bsd.c	Sun Feb 21 16:34:39 2010 -0800
@@ -54,6 +54,7 @@
 static grub_dl_t my_mod;
 static grub_addr_t entry, entry_hi, kern_start, kern_end;
 static grub_uint32_t bootflags;
+static grub_uint64_t zpool_guid = 0;
 static char *mod_buf;
 static grub_uint32_t mod_buf_len, mod_buf_max, kern_end_mdofs;
 static int is_elf_kernel, is_64bit;
@@ -559,7 +560,7 @@
     }
   else
     grub_unix_real_boot (entry, bootflags | FREEBSD_RB_BOOTINFO, bootdev,
-			 0, 0, 0, &bi, bi.tags, kern_end);
+			 zpool_guid ? 4 : 0, zpool_guid, &bi, bi.tags, kern_end);
 
   /* Not reached.  */
   return GRUB_ERR_NONE;
@@ -742,6 +743,7 @@
 
   grub_free (netbsd_root);
   netbsd_root = NULL;
+  zpool_guid = 0;
 
   return GRUB_ERR_NONE;
 }
@@ -954,6 +956,30 @@
   return result;
 }
 
+static void
+grub_fetch_zpool_guid(void)
+{
+  grub_device_t dev;
+  grub_fs_t fs;
+  char *uuid = NULL;
+
+  dev = grub_device_open (NULL);
+  if (! dev)
+    return;
+
+  fs = grub_fs_probe (dev);
+  if (! fs)
+    return;
+
+  if (grub_strcmp(fs->name, "zfs") != 0 ||
+      ! fs->uuid || fs->uuid (dev, &uuid) || !uuid)
+    return;
+
+  zpool_guid = grub_strtoull(uuid, NULL, 16);
+
+  grub_free (uuid);
+}
+
 static grub_err_t
 grub_cmd_freebsd (grub_extcmd_t cmd, int argc, char *argv[])
 {
@@ -1012,6 +1038,7 @@
 	    return err;
 	}
       grub_loader_set (grub_freebsd_boot, grub_bsd_unload, 1);
+      grub_fetch_zpool_guid();
     }
 
   return grub_errno;