setenv bootargs console=ttyS2,115200 root=/dev/mmcblk0p1 rootwait
ext4load mmc 1:1 $kernel_addr_r boot/kernel
ext4load mmc 1:1 $fdt_addr_r boot/rk3399-rock-pi-4b.dtb
booti $kernel_addr_r - $fdt_addr_r