vim ./opensource/uboot/board/ingenic/isvp_t31/board.c

在int board_early_init_f中添加如下代码：
	gpio_direction_input(25);
	gpio_direction_input(26);
	gpio_disable_pull_down(25);
	gpio_disable_pull_up(25);
	gpio_disable_pull_down(26);
	gpio_disable_pull_up(26);