Rooting MERAKI MR18

Hi

I connected uart to meraki mr18, but when I write

odm firmware part2 192.168.1.102:80/lede-ar71xx-nand-mr18-initramfs-kernel.bin

ip is not valid ... if I write

odm ip
cat: can not open '/ tmp / gateway_configuration': No such file or directory

How do I know which IP address have meraki, so I set up my computer on the same class?

thank you so much