This device is NOT RECOMMENDED for future use with OpenWrt due to low flash/ram.
DO NOT BUY DEVICES WITH 4MB FLASH / 32MB RAM if you intend to flash an up-to-date and secure OpenWrt version onto it! See 4/32 warning for details.

1) This device does not have sufficient resources (flash and/or RAM) to provide secure and reliable operation.
This means that even setting a password or changing simple network settings might not be possible any more, rendering the device effectively useless. See OpenWrt on 4/32 devices what you can do now.

2) OpenWrt support for this device has ended in 2022.
19.07.10 was the last official build for 4/32 devices.

Model CPU Wireless Flash RAM FCC ID
WNR834B v1 BCM3302 BCM4321 (PC-card) 4MB 16MB PY306100032
WNR834B v2 BCM3302 BCM4321 (integrated) 4MB 16MB PY307100061

Install OpenWrt (generic explanation)

FIXME Please add the installation procedure here.

Important Information

This router contains a hidden partition called board_data. This partition contains essential information for the bootloader to function. A patch was introduced in trunk revision 22475 that provided support for this router by skipping over this essential area of flash.
Architecture MIPS (low endian)
Vendor Broadcom
Bootloader CFE 1.0.37
System-On-Chip BCM4704KFBG
Processor BCM3302 v0.6
CPU Speed 264 MHz
Flash size 4 MiB
RAM size 16 MiB
Wireless BCM4321 b/g/n Wireless (v1:mini-PCI card, v2:integrated)
Ethernet BCM5325
Serial Yes


There are 3 sets of pads on the PCB of the WRN834B v2:

  • Solder pads - JTAG - near radio shield, top edge of board. (unconfirmed)
  • JP1 - Serial console, 3.3V, 115200/8/N
  • J12 - JTAG (Confirmed working)


3.3v TTL Serial, 1 row of six pins

Pin 1 3.3V
Pin 2 RXD
Pin 3 n/c
Pin 4 n/c
Pin 5 TXD
Pin 6 GND


10-pin JTAG, 2 rows of 5 pins

R374 through R378 and R343 remain un-populated

Pin 10 GND Pin 9 TCK
Pin 8 GND Pin 7 TMS
Pin 6 GND Pin 5 TDO
Pin 4 GND Pin 3 TDI
Pin 2 GND Pin 1 TRST

Solder pads

JTAG, 5 large pads

R470 TCK
R471 TMS
R472 TDO
R473 TDI
n/a TRST


There is 1 set of holes on the PCB of the WRN834B v1:

  • JP1 - Serial console, 3.3v, 115200/8/N
  • There are no obvious or labeled solder pads for JTAG on the v1 circuit board. There are numerous small test points labeled TPnn on both sides of the board which may provide JTAG capability. The vacant mini-PCI pads on top of the board are another possibility.


3.3V TTL Serial

Pin 1 GND
Pin 2 TXD
Pin 3 RXD
Pin 4 3.3V

If you were to somehow erase the board_data partition, this command will restore the data.

-flash:custom /window:1fc00000 /start:1ffe0000 /length:10000
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  • Last modified: 2024/02/12 08:58
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