diff --git a/stand/i386/loader/main.c b/stand/i386/loader/main.c
--- a/stand/i386/loader/main.c
+++ b/stand/i386/loader/main.c
@@ -387,7 +387,7 @@
 
 #ifdef LOADER_ZFS_SUPPORT
 	if (new_currdev.dd.d_dev->dv_type == DEVT_ZFS)
-		init_zfs_boot_options(zfs_fmtdev(&new_currdev));
+		init_zfs_boot_options(zfs_fmtdev(&new_currdev.dd));
 #endif
 
 	env_setenv("currdev", EV_VOLATILE, i386_fmtdev(&new_currdev),
diff --git a/stand/i386/zfsboot/zfsboot.c b/stand/i386/zfsboot/zfsboot.c
--- a/stand/i386/zfsboot/zfsboot.c
+++ b/stand/i386/zfsboot/zfsboot.c
@@ -226,7 +226,7 @@
 	 */
 	if (bdev != NULL && bdev->dd.d_dev->dv_type == DEVT_ZFS) {
 		/* set up proper device name string for ZFS */
-		strncpy(boot_devname, zfs_fmtdev(bdev), sizeof (boot_devname));
+		strncpy(boot_devname, zfs_fmtdev(&bdev->dd), sizeof (boot_devname));
 		if (zfs_get_bootonce(bdev, OS_BOOTONCE, cmd,
 		    sizeof(cmd)) == 0) {
 			nvlist_t *benv;
diff --git a/stand/libsa/zfs/devicename_stubs.c b/stand/libsa/zfs/devicename_stubs.c
--- a/stand/libsa/zfs/devicename_stubs.c
+++ b/stand/libsa/zfs/devicename_stubs.c
@@ -39,7 +39,7 @@
 
 __attribute__((weak))
 char *
-zfs_fmtdev(void *vdev)
+zfs_fmtdev(struct devdesc *vdev)
 {
     static char	buf[128];
 
diff --git a/stand/libsa/zfs/libzfs.h b/stand/libsa/zfs/libzfs.h
--- a/stand/libsa/zfs/libzfs.h
+++ b/stand/libsa/zfs/libzfs.h
@@ -50,7 +50,7 @@
 
 int	zfs_parsedev(struct zfs_devdesc *dev, const char *devspec,
 		     const char **path);
-char	*zfs_fmtdev(void *vdev);
+char	*zfs_fmtdev(struct devdesc *);
 int	zfs_probe_dev(const char *devname, uint64_t *pool_guid);
 int	zfs_list(const char *name);
 int	zfs_get_bootonce(void *, const char *, char *, size_t);
diff --git a/stand/libsa/zfs/zfs.c b/stand/libsa/zfs/zfs.c
--- a/stand/libsa/zfs/zfs.c
+++ b/stand/libsa/zfs/zfs.c
@@ -1583,7 +1583,7 @@
 	rv = 0;
 	/* This device is not set as currdev, mount us private copy. */
 	if (mount == NULL)
-		rv = zfs_mount(zfs_fmtdev(dev), NULL, (void **)&mount);
+		rv = zfs_mount(zfs_fmtdev(&dev->dd), NULL, (void **)&mount);
 
 	if (rv == 0) {
 		f->f_devdata = mount;
@@ -1681,7 +1681,7 @@
 }
 
 char *
-zfs_fmtdev(void *vdev)
+zfs_fmtdev(struct devdesc *vdev)
 {
 	static char		rootname[ZFS_MAXNAMELEN];
 	static char		buf[2 * ZFS_MAXNAMELEN + 8];
@@ -1689,7 +1689,7 @@
 	spa_t			*spa;
 
 	buf[0] = '\0';
-	if (dev->dd.d_dev->dv_type != DEVT_ZFS)
+	if (vdev->d_dev->dv_type != DEVT_ZFS)
 		return (buf);
 
 	/* Do we have any pools? */
diff --git a/stand/userboot/userboot/main.c b/stand/userboot/userboot/main.c
--- a/stand/userboot/userboot/main.c
+++ b/stand/userboot/userboot/main.c
@@ -260,7 +260,7 @@
 		bzero(&zdev, sizeof(zdev));
 		zdev.dd.d_dev = &zfs_dev;
 		
-		init_zfs_boot_options(zfs_fmtdev(&zdev));
+		init_zfs_boot_options(zfs_fmtdev(&zdev.dd));
 		dd = &zdev.dd;
 	} else
 #endif