Asus WL-500B
Version 1 of the device is supported in OpenWrt 1.0 (White Russian) and later. You need to install the openwrt-brcm-2.4-<type>.trx firmware images. Version 2 is unsupported, see Donations.
Bootloader: unknown System-On-Chip: Broadcom 4710 CPU Speed: 125 Mhz Flash size: 4 MB RAM: 16 MB Wireless: Mini-PCI Broadcom Ethernet: Robo switch BCM5325 USB: 1xUSB 1.1 LPT: yes Serial: yes, with external UART JTAG: no
If you have any problems reflashing via TFTP use this script http://jaffar.cs.msu.su/wl500g/recover.sh
if you can't download it, here's the code
#!/bin/bash
# recovery script for wl500g
#
# Copyright (C) 2004 by Oleg I. Vdovikin <oleg@cs.msu.su>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
if [ -z "$1" ] || [ ! -f $1 ]; then
echo Usage: $0 firmware.trx
cat << EOF
IMPORTANT:
1) be sure POWER led is flashing (If this is not a case
poweroff the device, push the reset button & power on
it again, then release button)
2) connect your pc to the LAN port
3) be sure your link is up and has an address in the
192.168.1.0/24 address range (and not the 192.168.1.1)
EOF
exit 0
fi
echo Confirming IP address setting...
echo -en "get ASUSSPACELINK\x01\x01\xa8\xc0 /dev/null\nquit\n" | tftp 192.168.1.1
echo Recovering 192.168.1.1 using $1...
echo -en "binary\nput $1 ASUSSPACELINK\nquit\n" | tftp 192.168.1.1
echo Please wait until leds stops flashing.
Thanks <hramrach> for the info 
.
The boot_wait NVRAM variable is on by default. Resetting to factory defaults via reset button or mtd erase nvram is not safe on this unit.
The version 1 units have a Broadcom wireless card, version 2 has a Ralink. There is version 2 with Ralink Wireless PCI Adapter RT2400 / RT2460, PCI device 1814:0101.