顶级目录：/bsp/kernel/kernel4.14

修改文件：arch/arm/boot/dts/su808-evk/su808-native.dts

chosen {
- 	stdout-path = &uart0;
- 	bootargs = "earlycon=sprd_serial,0x508d0000,115200n8
		console=ttyS0,115200n8 loglevel=4 init=/init root=/dev/ram0 rw androidboot.hardware=sl8541e_su808 vmalloc=360M androidboot.dtbo_idx=0 printk.devkmsg=on androidboot.boot_devices=soc/soc:ap-ahb/20600000.sdio";
+ 	bootargs = "loglevel=0 init=/init root=/dev/ram0 rw androidboot.hardware=sl8541e_su808 vmalloc=360M androidboot.dtbo_idx=0 printk.devkmsg=on androidboot.boot_devices=soc/soc:ap-ahb/20600000.sdio";
};

这里把kernel的日志级别也调成了0，可以一定程度的加快开机速度。