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My venerable Asus WL-500W finally kicked the digital bucket and forced me to upgrade. It was running dd-wrt so I went around and looked for something dd-wrt capable. I ended up finding the Asus RT-N66U which is dual 2.5/5GHz, openly dd-wrt friendly and carbon black.

Why would you want a 802.11N 5GHz band router you ask ? Well, first off 2.4GHz is saturated with noise if you live in a building. In my building channel 6 is useless (I mean, you can even associate) and everything else is overused. I need to go to channel 13/14 to make it actually work. The other reason is on 2.4GHz despite having N enabled you’ll probably also have B/G compatibility for older or cheaper devices so once that one G client connects your wireless speed will be pulled down. On the 5GHz you’ll only have N clients so you’ll be going full tilt. And what’s full tilt ? On 5GHz my macbookpro did around 115Mbps download versus about 80Mbps on 2.4GHz channel 13 and no G clients. The gigabit ethernet switch did OK, I measured about 800Mbps server to server. This are payload speeds, so actual wire speeds will be 8 to 10% higher.

Geting to this speeds means the CPU can’t be a slouch, the Asus RT-N66U has a 300MHz Broadcom MIPS chip and 265M RAM.

cat /proc/cpuinfo
system type          : Broadcom BCM5300 chip rev 1
processor          : 0
cpu model          : MIPS 74K V4.9
BogoMIPS          : 299.82
wait instruction     : no
microsecond timers     : yes
tlb_entries          : 64
extra interrupt vector     : no
hardware watchpoint     : yes
ASEs implemented     : mips16 dsp
shadow register sets     : 1
VCED exceptions          : not available
VCEI exceptions          : not available

It also has a roomy 32M flash which means plenty of space for fat firmwares. Also 64k of it can be used for nvram (which is used to save the configs) but more on that later. There’s 2 USB2.0 ports as usual and I haven’t craked warranty on mine yet but this pictures show a 3.3V serial header (J1), what looks like a JTAG header without the pins (J2) and a microSD slot people say is wired and works. For some reason ASUS left it locked inside the case and useless to mostly everybody. It was nice of them to put the serial header in there, I spent most of an evening soldering one into the 500W.

I booted the stock firmware long enough to confirm stuff worked. There’s a nice novelty on the N66U, the recovery mode (which is access by powering on with the reset button pressed until power starts blinking slowly) now has a small web server on where you can upload a firmware and clear nvram. Not only you don’t have to mess around with tftp to load firmware but also clearing settings doesn’t involve loading a specific mini build anymore. That particular bit saved my bacon once already while loading dd-wrt.

You’ll need a recent build of dd-wrt, their wiki says 18946 or 19342, I’m on 19342 mega and it’s working fine apart from not supporting 64k nvram hack yet. Despite the router having it, the bootstrap loader (CFE) doesn’t seem to know about it so the firmware must do a hack the use all the space. I’m not exactly sure how the hack (which is in stock firmware) works and what would happen when you clear nvram from recovery mode, most likely only half would get erased. There’s a thread about this here if you want to read more about it.
Flashing dd-wrt is straight forward, just follow the instructions and use the recovery mode mini http server.

/tech | edited on 2012/07/23 -- permalink, click to comment
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