Updated 5/12/2008 - Freshened links, updated DD-WRT info.
I received an email a few weeks back that asked me to see whether I could determine whether Linksys' WRT54G V5 wireless router is really as bad as users seem to have found it to be. For those of you unfamiliar with the situation, here's a short synopsis.
Linksys, like most consumer networking companies, constantly evolves the design of its products. Some changes are for cost reduction, others for performance reasons and others for reasons known only to the company. At any rate, these companies seem to think that consumers need not be concerned with the changes, since they in most cases don't change the model number of the product.
The WRT54G wireless router is probably one of Linksys' top five most popular products, with sales volumes in the "hundreds of thousands per month" according to this LinuxDevices article. It is Linux-based and also is probably the #1 "hacked" consumer networking product, with numerous alternative firmware distros available including Sveasoft, FreeWRT, DD-WRT, OpenWrt and Tomato.
Although loading any of them voids the product warranty, enough users have found the risk worth it due to the features they provide. Some simply provide access to transmit power settings, while others add features not available with Linksys' code.
For whatever reason, with the V5, Linksys decided to remove the hackability "feature", switching to the proprietary VxWorks embedded operating system that is used in other consumer networking products. The V5 also halves the amount of both RAM and flash memory to 8 and 2 MB respectively, which according to the LinuxDevices article lets Linksys come out ahead in cost reduction even with the additional cost of the VxWorks license fee. The reduced memory also serves as a deterrent for hackers who might want to find a way around the new bootloader.
The change didn't sit well with enough of Linksys' customers that the company responded to the outcry and created the WRT54GL (L for "Linux"), which is still loadable with alternative firmware. At the time of announcement, Linksys said it wouldn't guarantee how long the "L" would be available. But apparently it's popular enough that it has progressed to a "V1.1" version.