Teh WRT54G series launched in 2002 featuring a Broadcom BCM47xx 32-bit processor with 16MB RAM and a 4MB flash memory. The device functions as a router with wired 10/100 Mbps ethernet along with wireless 802.11bg. These devices continue to be a workhorse in WiFi everywhere and spawned several open source firmware projects. OpenWrt and dd-wrt both have their roots here. Almost as a trojan horse, they also brought about IoT in that the Broadcom chipset has since become the basis of the Raspberry Pi.
To "upgrade" from the command line with telnet, ssh or console access on a device already running busybox.
cd /tmp/ wget http://downloads.openwrt.org/backfire/10.03.1/brcm47xx/openwrt-brcm47xx-squashfs.trx mtd write /tmp/openwrt-brcm47xx-squashfs.trx
To "recover" with default settings, boot into failsafe mode and run
firstboot then restart.