Just to clarify - wrt54g method do not "reset" the chip, but causes CRC or invalid nvram content errors in the pmon, causing it to go to recover mode. wl500g on the other hand are always goes to recover mode if it detects that RESTORE button is pressed during the power on.
It does not matter who has produced the FLASH.
Also, Reset PIN will not clear FLASH, but reset the internal CPU. This will not help you.