Linksys WRT350N v1.0

Hardware Versions

Useful for identifying shrinkwrapped units. The S/N can be found on the box, below the UPC barcode.

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Model S/N
WRT350N v1.0 – Not available in Europe? CNQ01
WRT350N v2.0 – Only available in Europe? SNQ00

Hardware Highlights

CPU Ram Flash Network Gigabit USB Serial JTag
Broadcom BCM4785@300MHz 32MB 8MB 4x1 Yes Yes Yes Yes

See paragraphs Hardware for more details.

Warnings / Gotchas

Flashing the pre-built openwrt-wrt350n_v1-squashfs.bin from downloads.openwrt.org could very well disable all ethernet ports on the router, forcing you to install a serial port to recover. Search the forums and you'll see that happened to a bunch of people.

Installation

OpenWRT Firmware

It is possible to run an older kamikaze bcrm-2.4 version of OpenWRT on the v1.0 hardware. You may need to build this yourself to enable the required drivers.

Support for the wrt350n v1.0 was added to SVN with changesets 11466-11471 (broadcom 2.4 build). In order to use the device, make sure the bcm57xx package is included in your image (selected as * in menuconfig). Without this package installed, the switch will not come up and you'll have to use a serial console to recover.

Wireless works as long as kmod-brcm-wl-mimo is installed. USB also works with kmod-usb-ohci, I have tested it as a print server with p9100d.

A note about NVRAM

The switch in the wrt350n v1 is a little different from the older switch chips. By default, it will forward packets between the LAN and WAN, much like a normal switch. This is a problem during bootup because boot_wait will activate the switch to wait for an image. The only way I could find to make the switch not forward packets on bootup was to set the following NVRAM variables:

Disabling boot_wait is a bad idea, so make sure you really need it off before doing so.

nvram set boot_wait=off
nvram set manual_boot_nv=1
nvram unset disabled_57xx
nvram commit

CFE Bootloader

The CFE bootloader brings up the ethernet with IP 192.168.1.1 and listens for a TFTP "put" for a few seconds. If a file is uploaded via TFTP, the header is read and the board type and checksum is validated before it is programmed into flash. The default firmware image from OpenWRT may not have the required header. This can be dealt with via the serial port like so:

Start sending the firmware from a linux computer on the same network:

echo -e "binary\nrexmt 1\ntimeout 60\ntrace\nput openwrt-wrt350n_v1-squashfs.bin\n" | tftp 192.168.1.1
Receive the firmware file and program it to flash:
flash -ctheader : flash1.trx

Hardware

The WRT350N v1.0 is based on the Broadcom 4785 r2 running at 300MHz cpu. It has 8 MB flash and 32 MB SDRAM. The wireless NIC is a Broadcom Cardbus card with maybe a BCM5397 Chipset on the switch. The WRT350N runs 802.11 B, G, and Draft N wireless protocols. It provides 4 gigabit LAN ports, 1 WAN port and a USB 'storage link' port.

Opening/closing the case

The silver panels on the top and bottom are snapped into place at the rear of the unit only. They have a slide fitting at the front of the unit, so don't pry them apart at the front. The font of the case slides forward and off. Removing the silver covers reveals the screws, which are a star and center pin type. Once these are removed, the case come apart easily.

Serial Port Mod

http://cascade.dyndns.org/~datagarbage/wrt350n.html

Connector JB3 has TTL 3.3v UART

Pin Function
1 3.3v
2 Tx
3 Rx
4 unknown
5 GND

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toh/linksys/wrt350nv1.txt · Last modified: 2012/12/29 04:46 by billf