GRUB_ENVMAP
nvlist_find(nvl, GRUB_ENVMAP, DATA_TYPE_STRING, NULL,
nvlist_add_string(benv, GRUB_ENVMAP, be->vbe_bootenv);
fnvlist_add_string(required, GRUB_ENVMAP, "test");
fnvlist_add_string(bootenv, GRUB_ENVMAP,
if (nvlist_lookup_string(env, GRUB_ENVMAP, &nvbuf) == 0) {