In practice, this means that you can have all the features you need with none of the bloat, powered by a Linux kernel that's more recent than most other distributions.
Please visit the version history page for an overview of previous releases.
The general method for picking the right image is visiting the Table of Hardware (which has replaced the old version of the Table), then matching the "Platform & Frequency" of your device with the image you're downloading. Sometimes, the "Status" column will have additional information for your device, such as building its image or device-specific installation instructions.
If there isn't a pre-built image for your device, follow the Building OpenWrt instructions to build a custom image.
Any bugs in the firmware should be reported via the ticket system.
The branch trunk is where the current coding happens. It supports more hardware but sometimes doesn't compile. It can be built from sources:
Or some limited snapshots are available, though it's highly advisable that you check the dates on the files before downloading them:
At any time, there are two branches of OpenWrt: the latest stable (Backfire) or the latest nightly build (Attitude Adjustment) . There are advantages and disadvantages to both choices.
First, there is the usual difference that the nightly build contains all latest updates and fixes, and allows you to use all OpenWrt features currently supported on your router. However, this also means you could hit a bug which was only recently introduced and has not been fixed yet. The release is tested more thoroughly, and is usually safer. Generally, if you wish to play it safe, install the release; if you wish to experiment and write custom scripts, install the nightly build.
Keep in mind that the firmware recovery mode of the DIR-825 allows you to boot from an alternative firmware and re-flash your router, even if you bricked it. This should make it a little safer to use the nightly build even if you get cold feet.
Secondly, there is a small difference I noticed myself between these versions: as the release is more polished, you will have the Luci web interface installed by default, where as with the nightly you need to install it via SSH yourself first. This confirms once again the nightly is tailored for the adventurous type, where as the release is safer and easier.
One small note: as of the time of writing, I noticed the aiccu package for SixXS IPv6 tunnels is not working on the Backfire release, while it is on the nightly builds.
Once you have decided which version you are going to install, grab the image from the download server.
For the release, go to: http://downloads.openwrt.org/backfire/10.03.1/ar71xx/ (substitute 10.03.1 with the latest version of the backfire release, if necessary substitue backfire as well with the name of the latest release).
For the nightly, go to: http://downloads.openwrt.org/snapshots/trunk/ar71xx/
In both cases, grab the file with dir-825 in the filename.
Now you have to decide if you wish the squashfs or jffs2 version. The difference being the squashfs version uses a read-only file system with a read-write overlay; and the jffs2 version uses a read-write file system. In the end, you can make modifications to both versions, but you are either making it straight on the file system or on the transparent overlay. The overlay version (squashfs) is slightly safer, where as the jffs2 version is more powerful. For normal usage, squashfs is more than enough.
Finally, decide which version you need:
If you are going to install via the normal DIR-825 firmware upload, grab the file with factory in the name.
If you are going to the use backup loader (see below for instructions), grab the file with backup-loader in the name. If you bricked your router, this is the only way to go.
If you already have OpenWRT and you wish to upgrade while keeping your settings, use the file with sysupgrade in the name.