SUSFinder
Set recovery mode IP and flash firmware to ASUS WL-500gP router
...This utility do essentially the same thing as ASUS Firmware Restoration Utility, except that it relies on the external 'atftp' program to do the TFTP firmware flashing part.
Currently, SUSFinder is written in ANSI C with POSIX API, thus should be portable to most Unix-like platform (including Cygwin).