register_command(cmd_ctx, nand_cmd, "dump", handle_nand_dump_command, COMMAND_EXEC,
                                                 "dump from NAND flash device <num> <filename> <offset> <size> [options]");
                register_command(cmd_ctx, nand_cmd, "write", handle_nand_write_command, COMMAND_EXEC,
-                                                "write to NAND flash device <num> <filename> <offset> [options]");
+                                                "write to NAND flash device <num> <filename> <offset> [oob_raw|oob_only]");
                register_command(cmd_ctx, nand_cmd, "raw_access", handle_nand_raw_access_command, COMMAND_EXEC,
                                                 "raw access to NAND flash device <num> ['enable'|'disable']");
        }
                u8 *oob = NULL;
                u32 oob_size = 0;
                        
-               duration_start_measure(&duration);
                offset = strtoul(args[2], NULL, 0);
                
                if (argc > 3)
                                else
                                {
                                        command_print(cmd_ctx, "unknown option: %s", args[i]);
+                                       return ERROR_COMMAND_SYNTAX_ERROR;
                                }
                        }
                }
                
+               duration_start_measure(&duration);
+
                if (fileio_open(&fileio, args[1], FILEIO_READ, FILEIO_BINARY) != ERROR_OK)
                {
                        return ERROR_OK;