I've just installed the same hardware and it did work : Cisco ON100 K9 V02.
The wiki entry is almost ok. The two separate files thing is when you do build from the sources. Don't go this way, just go for the first option : downloading the firmware.
My two cents : don't use the firmware url given in the wiki - it's the snapshot version - go for the stable one here :
http://downloads.openwrt.org/releases/18.06.1/targets/kirkwood/generic/
there you want the : cisco_on100-squashfs-factory.bin
I've renamed this long file to "squashfs-factory.bin" and changed accordingly the commands in the U Boot command line to :
dhcp
setenv serverip 192.168.1.66
tftpboot ${loadaddr} squashfs-factory.bin
nand erase 0x0c0000 ${filesize}
nand write ${loadaddr} 0x0c0000 ${filesize}
As you see, my own PC (windows 7) which was running the TFTP server (in my case PumpKIN) has an IP address of 192.168.1.66 . Of course you will have to change this parameter to fit your own configuration.
There's however a typo that must be corrected in the wiki ( Cisco ON-100 k9_v01 ) : backslashes must be added to escape the semicolons in the line :
setenv bootcmd nand read ${loadaddr} 0x0c0000 0x540000; setenv bootargs; bootm
So the correct line should be :
setenv bootcmd nand read ${loadaddr} 0x0c0000 0x540000 \; setenv bootargs \; bootm
saveenv
But once again, it works with the V02, and you can check it easily in the pictures there :
https://openwrt.org/_detail/media/cisco/on100_base.jpg?id=toh%3Acisco%3Acisco_on-100_k9_v01
As you can see, the hardware used is indeed a V02, despite the topic name !!!
P.S. : One critical warning : when you'll install openwrt on your Cisco ON100-K9, take care to remove from your lan the device having the IP adress 192.168.1.1. It's the one that your OpenWrt device will assign to itself by default. So have, for example, a lan on the 192.168.1.xxx range and be careful to assign the router address to 192.168.1.254 (and set it as the gateway address on the other devices living on this lan, at least for the time of the Openwrt install).