-#if !defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL)
-#define CONFIG_ENV_IS_IN_FLASH 1 /* use FLASH for environ vars */
+#if defined(CONFIG_NAND_U_BOOT) || defined(CONFIG_NAND_SPL)
+#define CONFIG_ENV_IS_IN_NAND /* use NAND for environ vars */
+#define CONFIG_ENV_IS_EMBEDDED /* use embedded environment */
+#elif defined(CONFIG_SYS_RAMBOOT)
+#define CONFIG_ENV_IS_NOWHERE /* Store env in memory only */
+#define CONFIG_ENV_SIZE (8 << 10)
+/*
+ * In RAM-booting version, we have no environment storage. So we need to
+ * provide at least preliminary MAC addresses for the 4xx EMAC driver to
+ * register the interfaces. Those two addresses are generated via the
+ * tools/gen_eth_addr tool and should only be used in a closed laboratory
+ * environment.
+ */
+#define CONFIG_ETHADDR 4a:56:49:22:3e:43
+#define CONFIG_ETH1ADDR 02:93:53:d5:06:98