Link for File download: http://www.dd-wrt.com/dd-wrtv2/downloads/v24/Broadcom/Broadcom%20Generic/dd-wrt.v24_std_generic.bin
Install Instructions: http://www.dd-wrt.com/phpBB2/viewtopic.php?t=62942&highlight=rosewill+rnxgx4
2~ input username/password, default are admin/guest
3~ click the "System Management" at the bottom left
4~ click "Firmware Upgrade" Tab.
5~ click "browse" , upgrade the dd-wrt file you've downloaded from dd-wrt website.
6~ wait for 2~3 minutes , then unplug the powerline ,and plug in, wait about 2 minutes, then go to 192.168.1.1, then done.
DD-WRT login default username/password is root/admin
if you can't see the first page of DD-WRT firmware, "Refresh" might help.
In addition, this model needs to go to "vlan option", uncheck the “W”column, then "save" and “apply”, then check “W” again then "save" and "apply".
Some MAC address might be cleaned when you flashed to DD-WRT (nvram cleaned), but it's easy to be sovled. Here is my suggesion:
1. write down the original MAC address in your "Rosewill" firmware (LAN MAC address)
2. After flashed to DD-WRT, the MAC will be changed to 00:90:4c:c0:00:01 or other similar numbers.
3. telnet 192.168.1.1 and then input login/pw as root/admin
4. type command as following (xx:xx:xx:xx:xx:xx is the original LAN MAC address in first step)
nvram set et0macaddr=xx:xx:xx:xx:xx:xx
For Rosewill it should be nvram set et2macaddr=Wireless Mac Address