wrt54g v7 firmware online: Firmware-update: Linksys WRT54G 7.00.4 - Computer - Tweakers,Linksys Official Support,Linksys WRT54G v8.0 & v8.2 - DD-WRT Wiki,Need firmware update for Linksys WRT54GS - Cisco Community,
Some of the KF discussions I've been following suggest updating the router's firmware so the KF will recognize and connect to it. I contacted Cisco and was told that no firmware updates are available for my router since it is out of warranty.
I am searching for the latest firmware upgrade for the Linksys WRT54G V8 router. Since the whole Linksys/Cisco line of these products were sold to Belkin, firmware upgrades for this model appear to have been stricken from the internet.
All Linksys firmware upgrades are posted on the Linksys website at www.linksys.com, where they can be downloaded for free. To upgrade the Router's firmware, use the System tab of the Router's web-based utility.
After waiting for around 4 or 5 minutes, you have the original WRT54G2 firmware. From then on, you can use all the updates for the wrt54g2 that linksys makes available. Now, to answer your second question, if you want to go back to dd-wrt, you have to use the WRT54G2 v1.0 method with the WRT54G2 v1.0 firmware.