Ok I have to admit that I am a DDWRT fan because of it's tons of features but have had stability issues with My Buffalo Router and I just couldn't get OpenVpn to work on my DDWRT. I looked at Tomato and the downloads here do not have an OpenVPN version. I did some searching and found an awesome build of Tomato with OpenVPN support and it works like a charm with my VPN service.
I thought I would miss DDWRT but this new firmware is so stable and it works flawlessly with OpenVPN and it is so simple to configure. I would advise Tomato for the simple configuration and this build I found has everything a pretty advanced user would like to incluse USB support.
Now I have read several threads on how to install tomato and even bricked my router before getting it to work. The basic concept of installing Tomato is to install DDWRT from the original firmware and then from DDWRT installing Tomato. I bricked my router but in examining several other threads I read that it had to do with the builds I was using. In order to get this mega tomato build I had to use the Mega build of DDWRT. I read it had something to do with the partition sizes DDWRT uses. I am not an expert but I can tell you how I got it to install from the factory firmware once I de-bricked it.
Please take into consideration that this is not a beginners guide. It assumes that you have a familiarity with getting to firmware GUI and how to do 30/30/30 resets
Here Goes:
1. First download the Mega version of DDWRT at http://www.myopenrouter.com/download/21278/DD-WRT-Mega-BETA-svn-14826-2010-07-18-for-WNR3500L/
2. Next download the Mega Tomato VPN Firmware at http://sourceforge.net/projects/tomatousb/
3. Next make sure you have the factory firmware on your WNR3500L
4. Next go to upgrade in the factory firmware and upgrade as you normally would the factory firmware choosing the mega DDWRT bin file that you extracted from the zip download.
5. After the upgrade is complete wait for all the lights to come back on as normal.
6. Now conduct a 30/30/30 reset to make sure your fresh
7. Extract tomato .trx file from the archive that you downloaded and chenge the .trx to .bin by renaming the file
8. Log in to DDWRT and go to admin tab to conduct second upgrade.
9. Choose the renamed .bin file and upgrade. Wait a few minutes when complete and you see the lights come on as normal.
10. Conduct a 30/30/30 reset again or else you won't be able to log in to the router.
11. Finished!
Tomato Mega with USB support installed!
Hope this helps!
Hm...
From what I can tell, you should probably update that Tomato firmware URL. It's a bit misleading. It's a direct link to tomato-K26USB-1.28.9051MIPSR2-beta22-Ext.rar, which is not a mega VPN build. If you're going to use that URL you should note to not use the "Download Now" button but rather the OR "View all files" link to find a listing that includes the mega builds, among the rest.