Linksys E4200 v1

Overview
"3763-40700105R" and the Cisco logo is silkscreened on the board.
 * This router uses Galtronics antennas.
 * Note: Three antennas are used by the 2.4 GHz radio, but it's still a 2T2R radio..

The default SSID pattern for this device is CiscoXXXXXX on both bands,
 * where XXXXX is the last 5 characters of the serial number.

Wikis

 * On the DD-WRT wiki

Reviews

 * Review on SmallNetBuilder

Forum threads

 * On the TomatoUSB forums
 * On the DD-WRT forums
 * The v1 serial numbers appear to start with 01C10C..

Firmware projects
This device is supported by...
 * Victeks Tomato RAF' builds
 * Shibbys Tomato' builds (K26 and K26RT-N)
 * Toastmans Tomato' builds

Warnings

 * The E4200 is very sensitive to the nvram size. The only safe nvram size identified for this router is an nvram size of 60kB. Recovery from a firmware with the wrong nvram size requires use of a jtag cable to erase the nvram.1


 * Support for the E4200 is still very much a work in progress at this time, outstanding issues reported have included WAN stability, and both 2.4GHz and 5GHz Radio stability.

Flashing Process

 * Perform these steps when flashing from the stock linksys GUI:


 * 1) Disconnect all cables and wireless clients.
 * 2) Perform a 30/30/30 reset on the device.
 * 3) Flash the latest E4200 specific mini build (dd-wrt.v24- _NEWD-2_K2.6_mini-e4200.bin) to the router.
 * 4) The E4200 specific mini builds are also -nv60k builds, they just aren't labeled as such.
 * 5) Wait approximately 5 minutes for the flashing process to complete.
 * 6) Perform a 30/30/30 after the device has successfully updated.
 * 7) Flash to larger build of your choosing (Mega, Big, std_usb_nas, OpenVPN, VoIP.)
 * 8) WARNING Only flash -nv60k builds, flashing anything else to the router will brick it as noted above (dd-wrt.v24- _NEWD-2_K2.6_ -nv60k.bin)
 * 9) If flashing to another build always perform a 30/30/30 before and after flashing

Flashing Tomato

 * tomato-E4200-test-5 - Test Build

Upgrading dd-wrt
If dd-wrt 17084 and up is already on the router, builds with nv60k in the name can be used for upgrade.

Reverting dd-wrt

 * You can always revert back to stock firmware.
 * Download the latest E4200 firmware from linksys site.


 * 1) Disconnect all cables and wireless clients.
 * 2) Perform a 30/30/30 reset on the device.
 * 3) Login and select the stock firmware file and flash, make sure to select "reset to defaults" on the drop down menu when flashing.
 * 4) Wait approximately 5 minutes for the flashing process to complete.
 * 5) Perform a 30/30/30 after the device has successfully updated.

nv60k
Eko

Just a note on upgrading e2000, e3000 and e4200 routers already running dd-wrt. These need -nv60k.bin builds, but this will work only from now on. So for initial upgrade use proper mini-eXXXX.bin build and then upgrade with -nv60k.bin build. If you flash a -nv64k.bin, your E4200 will bricked!

Wireless-N Configuration

 * As is explained in http://www.dd-wrt.com/wiki/index.php/Wireless-N_Configuration make sure that you use AES security for your wireless N network. Do not use TKIP or the wireless speed will revert to the g standard and that would be a pity. AES+TKIP is also allowed.


 * Both the 2.4 and 5GHz Radios run at a stock transmitting power of 100mW, decreasing the transmitting power to a value between 40 & 50mW has seemed to help stability.

5GHz Wireless Transfer Speed Tips
These are suggestions that are being recommended inside the E4200 forums thread to improve wireless performance on the 5GHz radio. Recommendation from LiteUp! and basmaf


 * Enable Frame burst
 * Set Afterburner to Auto (this will only have an effect if your wireless clients use Broadcom radios. Disable Afterburner, if you use two Routers in AP <->Client Bridge-Mode)
 * Highest transfer rates are being achieved on channels 100-128. Do not set channel to Auto!
 * Be patient, let SNR settle down before testing speeds.