We connect a PC to one of the LAN
jacks of the WRT54G.
The WAN jacks is connected to our gateway.
The latest OpenWRT version at the time of writing is backfire 10.03, and according to the docs on flashing the device, we should pick an image according to chipset and clock frequency.
user@PC:~$ wget http://downloads.openwrt.org/backfire/10.03/brcm47xx/openwrt-brcm47xx-squashfs.trx
user@PC:~$ scp openwrt-brcm47xx-squashfs.trx root@192.168.1.1:/tmp
root@WRT54G:~$ mtd -r write /tmp/openwrt-brcm47xx-squashfs.trx linux
Unlocking linux ...
Writing from /tmp/openwrt-brcm47xx-squashfs.trx to linux ... [w]
Rebooting ...