• linux
  • wireless
  • opensource

Running dd-wrt on a Linksys wrt1900ACS

I've used dd-wrt on many Linksys WRT54G routers over the years at work and at home. These blue routers, first released in 2002, became classics and in large part because Linksys allowed the open source community to develop replacement firmware for them. The additional capabilities and enhanced (or at least more up to date) security that dd-wrt provided over stock Linksys firmware extended the life of these little routers well past the point when leaving them stock would have been dangerous, and kept me using their older 802.11g technology for years even as 11n was getting popular.

Linksys_AdWhen an "homage" model was revealed that looked almost exactly like the original wrt54g and held out the additional promise of being "open source ready" I was all in. This Linksys WRT1900ACS may look a lot like my old Linksys routers (at that time Linksys was a division of Cisco) but in 2013 Linksys had been acquired by Belkin so I was pretty dubious about quality. I haven't had any problems with the unit running the stock firmware, though I do miss a lot of features I was used to in dd-wrt.

Amazon has it (shipping from them) currently for $367. You can read reviews of it there which is always fun. I know I paid quite a bit less for it when I got mine and Linksys has the list price as $200, but its not available for sale there. There were cheaper routers to be had for sure but if past experience is any guide, firmware updates for these kinds of devices would stop appearing right around the time a huge exploit for it would appear. Proprietary firmware made it impossible for anyone besides the manufacturer to fix security issues so if they decided to stop publishing updates... An open source firmware helps ensure that updates would keep coming since generally the people motivated enough to fix problems are those affected by them and when fixing a device is possible, there are always some owners willing to do it and share the wealth. I felt the pledge of open source was enough to make up for possible build quality issues.

The Marvell chip

One thing I noticed right away was the that the Linksys was not based on the more popular Broadcom or Qualcomm's Atheros chips, but with a Marvell chip. The Marvell SoC (System on Chip) found in the wrt1900acs is a dual core running at 1.6GHz which puts it at the higher end of many routers on the market at its date of release.


Although an open platform was touted from the initial release of the wrt1900, the announced partnership was with OpenWRT another open firmware project which I had never personally used. The release, in May of 2015, was later marred somewhat as OpenWRT members disagreed about direction of the project and ended up forking it with many developers leaving to form LEDE. Thankfully, disagreements have since been settled and the project is working together again under the official OpenWRT branding as of Jan, 2018. OpenWRT may be back on track, but support from them for the wrt1900 doesn't seem to have moved along very much as their offical support page still warns (as of Apr, 2018) that the project is stalled.

David Simpson took it for a spin back in 2015 and while his apparent success was heartening, my lack of experience with OpenWRT and desire to not brick my expensive new router was enough of a deterrent.


Once the source is released, its usually not long before you start seeing new projects forked from that code appearing. A forum post appeared on dd-wrt's forums announcing the release of a new build 28374 for this hardware in Nov, 2015 just 6 months after the official release and the last comment (by htismage) on that initial post makes the bold claim that

I honestly feel like for the first time since buying this router 18 months ago, I've finally unlocked it's full potential."

and lists some of the reasons I've always liked dd-wrt as well: the diagnostics, stability, and improved performance. With the added incentive that it didn't even require a full 30-30-30 reset and was upgraded from within the stock GUI!

Still far too soon for me to jump in.

staying up to date on progress

I've been following the development on the dd-wrt forums for Marvell based routers and what follows are my notes.

You don't need to "flash" back to stock. You reset the router and reboot it three times to get back to stock.

* This was written up a bit clearer in a later thread:
    * Switch off the router with the power switch on the back.
    * Power the router back on, and the power light will light.
    * As soon as you see the power light go out, switch off the power switch.
    * Repeat this 3 times.
    * On the 3rd time the router will boot from the other partition.

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