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Belkin F5D8235-4

Belkin's N+ Wireless Router (F5D8235-4) features a USB storage port on the back of the router. This router also features Gigabit Ethernet. The N+ router is based on the draft 802.11n 2.0.

Supported Versions

Hardware Highlights

Version Subversion CPU Ram Flash Network Network Switch USB Serial JTag
v1 Ralink RT2880@266MHz 32MiB 8MiB 5 x GBit 1x 2.0 Yes ?
v2 < 2033 Ralink RT3052@384MHz 32MiB 8MiB 5 x GBit RTL8366RB 1x 2.0 Yes ?
v2 > 2033 Ralink RT3052@384MHz 32MiB 8MiB 5 x GBit RTL8366SR 1x 2.0 Yes ?

The Subversion is most likely, some may not match the rule.

WARNING There are open tickets which report a not working Ethernet with V2 FIXME Outdated information? Please verify and update as appropriate.

CAUTION Before starting any of these endeavors if your router does not have a serial port from factory make one first for disaster recovery with USB to TTL Serial Cable and solder it to the unoccupied 9-pin USB 2.0. That possibly explains why there are reports of USB 3.0 not working when going serial.

F5D8235-4 v1 sticker with GUI showing V1000 that uses stock f5d8235v1_ww_1.01.28.bin firmware is a high brick risk. Read this if you are thinking about flashing Belkin with this software. If you are so daring reset modem before and after attempting any OpenWrt. What works here Belkin support page will not be the same when you use this software. I used v1 instead of v2 due to the Ethernet port problem. My results were worse. Serial to TTL is being sent to me from China as RadioShack is out of business! If it is any assurance if things go South a new and better plus smaller AC extender is $20 whereas a used F5D8235-4 is $30 that only produces N.

What falsely encouraged me were the testimonials of people doing this error-free using the GUI menu to flash. I did use the GUI menu method and failed to reset modem first. There are no organized uniform instructions and this is 2 projects combined. USE AT YOUR OWN RISK.


via OEM webinterface

Belkin F5D8235-4 v1 can be flashed to LEDE via Belkin web UI1):

  1. In your browser, go to (Belkin stock UI) and log in
  2. Go to
  3. Set “firmware header checking” to 0 and apply
  4. In your browser, go again to http://192.168.**2**.1/ and flash the sysupgrade image via the firmware update menu
  5. After reboot, LEDE should be accessible via ssh under

Enable telnet

  • Enable telnet: Go to http://belkin/ver.htm and set “Start telnetd for debug” parameter to 1.
    You will also need to add telnetd binary to firmware image or recompile busybox with telnetd applet.
  • Disable telnet: Go to http://belkin/ver.htm and set “Start telnetd for debug” parameter to 0.

U-Boot environment

Note: The bootdelay is 1 seconds or less. You really need to shorten the time window it takes your machine to establish a connection to the router. “If you still miss selecting needed operation number, then just let it finish booting, type reboot and start pressing operation number you'll want to pass to U-Boot.”

U-Boot 1.1.3 (Jun 12 2008 - 15:40:46)

Board: RT2880 DRAM:  32 MB
relocate_code Pointer at: 8bfa8000

 twe0 set to 

 toe0 set to 
flash_protect ON: from 0xBC400000 to 0xBC424D03
protect on 71
protect on 72
protect on 73
flash_protect ON: from 0xBC430000 to 0xBC43FFFF
protect on 74
*** Warning - bad CRC, using default environment

Ralink UBoot Version: 2.0
ASIC 2880_MP (MAC to GigaMAC Mode)
Total memory: 32Mbytes
Date:Jun 12 2008  Time:15:40:46
 D-CACHE set to 4 way
 I-CACHE set to 4 way

 ##### The CPU freq = 266 MHZ ####

 SDRAM bus set to 32 bit
 SDRAM size =32 Mbytes

Please choose the operation:
   1: Load system code to SDRAM via TFTP.
   2: Load system code then write to Flash via TFTP.
   3: Boot system code via Flash (default).
   4: Entr boot command line interface.
   5: Load ucos code to SDRAM via TFTP.

You choosed 4

Eth0 (10/100-M)
 enetvar=ethaddr,Eth addr:00:AA:BB:CC:DD:18

 eth_current->name = Eth0 (10/100-M)

4: System Enter Boot Command Line Interface.

U-Boot 1.1.3 (Jun 12 2008 - 15:40:46)

 main_loop !!

 In main_loop !!


RT2880 # help
?       - alias for 'help'
boot    - boot default, i.e., run 'bootcmd'
bootd   - boot default, i.e., run 'bootcmd'
bootm   - boot application image from memory
bootp   - boot image via network using BootP/TFTP protocol
cp      - memory copy
echo    - echo args to console
erase   - erase FLASH memory
help    - print online help
loopback   - Ralink eth loopback test !!
md      - memory display
mdio   - Ralink PHY register R/W command !!
mm      - memory modify (auto-incrementing)
mw      - memory write (fill)
nm      - memory modify (constant address)
printenv- print environment variables
protect - enable or disable FLASH write protection
run     - run commands in an environment variable
saveenv - save environment variables to persistent storage
setenv  - set environment variables
spicmd  - read/write data from/to eeprom or vtss
tftpboot- boot image via network using TFTP protocol
version - print monitor version
RT2880 #

RT2880 # printenv
ramargs=setenv bootargs root=/dev/ram rw
addip=setenv bootargs $(bootargs) ip=$(ipaddr):$(serverip):$(gatewayip):$(netmaf
addmisc=setenv bootargs $(bootargs) console=ttyS0,$(baudrate) ethaddr=$(ethaddr1
flash_self=run ramargs addip addmisc;bootm $(kernel_addr) $(ramdisk_addr)
load=tftp 8A100000 $(u-boot)
u_b=protect off 1:0-1;era 1:0-1;cp.b 8A100000 BC400000 $(filesize)
loadfs=tftp 8A100000 root.cramfs
u_fs=era bc540000 bc83ffff;cp.b 8A100000 BC540000 $(filesize)
test_tftp=tftp 8A100000 root.cramfs;run test_tftp
ethact=Eth0 (10/100-M)

Environment size: 783/65532 bytes
RT2880 #



CPU: Ralink RT2880F
Flash: 8MB
Wi-Fi: Ralink RT2820
Switch: Realtek RTL8366SR


Serial port

Serials console baudrate is : 57600,8n1

Serial console is available on J6, pinout as follow :

TXD 0 0 VCC 3.3V
    0 0 VCC 3.3V
    0 0 GND

System Information

1) cat /proc/version

Linux version 2.4.30 (root@localhost.localdomain) (gcc version 3.3.6) #297 Wed Jan 21 01:42:19 CST 2009

2) cat /proc/cpuinfo

system type             : Palmchip Surfboard
processor               : 0
cpu model               : unknown V6.12
BogoMIPS                : 266.24
wait instruction        : no
microsecond timers      : yes
tlb_entries             : 16
extra interrupt vector  : yes
hardware watchpoint     : no
VCED exceptions         : not available
VCEI exceptions         : not available

3) cat /proc/meminfo

        total:    used:    free:  shared: buffers:  cached:
Mem:  28803072 26460160  2342912        0  2109440  8671232
Swap:        0        0        0
MemTotal:        28128 kB
MemFree:          2288 kB
MemShared:           0 kB
Buffers:          2060 kB
Cached:           8468 kB
SwapCached:          0 kB
Active:           5008 kB
Inactive:         5584 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:        28128 kB
LowFree:          2288 kB
SwapTotal:           0 kB
SwapFree:            0 kB

4) cat /proc/mtd

dev:    size   erasesize  name
mtd0: 00050000 00010000 "uboot"
mtd1: 00790000 00010000 "Kernel and Rootfs"
mtd2: 00660000 00010000 "Rootfs"
mtd3: 00010000 00010000 "Nvram"
mtd4: 00010000 00010000 "Factory"

5) cat /proc/interrupts

  2:          0       Surfboard  ehci_hcd, usb-ohci
  3:     103797       Surfboard  eth2
  4:     145937       Surfboard  ra0
  6:      97185       Surfboard  timer
  7:          0       Surfboard  rt2880_gpio
  8:        175       Surfboard  serial

ERR:          0

6) ps

  PID  Uid     VmSize Stat Command
    1 root        236 S   /bin/init
    2 root            SW  [keventd]
    3 root            SWN [ksoftirqd_CPU0]
    4 root            SW  [kswapd]
    5 root            SW  [bdflush]
    6 root            SW  [kupdated]
   10 root            SW  [mtdblockd]
   11 root            SW  [khubd]
   20 root        384 S   /bin/sh
   39 root        480 S   resetC
   42 root        776 S < gpio_ctrl
   44 root        384 S   psmon
   93 root            SW  [rtmpWscHandle]
  137 root        340 S   syslogd
  140 root       1072 S < httpd
  148 root        220 S   easyconf
  150 root        296 S   easystorage
  170 root        300 S   telnetd
  180 root        948 S   ledctrl
  190 root        272 S   if_traffic
  192 root        908 S   wan_connect
  222 root        340 S   lld2d br0
  243 root        776 S   pppd vlan2
  400 root       1036 S   dnsmasq -z br0 -n -o -u root -r /var/resolv.conf -H /
  414 root        896 S   /usr/sbin/udhcpd /tmp/udhcpd.conf
  464 root        392 S   /bin/radvd -C /var/radvd.conf -d 1
  940 root       1440 S   /usr/local/samba/sbin/nmbd
 1093 root       1500 S   /usr/local/samba/sbin/smbd
 1250 root        516 S   /usr/sbin/conn_log
 5759 guest       496 S   -sh
 8901 guest       488 S   -sh
 9652 guest       344 R   ps

GPL source code

Buildable source code is available at

  • For 1.01.19 firmware - F5D8235v1-1.01.19-GPL.tar.gz
  • For 1.01.21 firmware - F5D8235v1-1.01.21-GPL.tar.gz
  • For 1.01.24 firmware - F5D8235v1-1.00.24-GPL.tar.gz


toh/belkin/f5d8235-4.txt · Last modified: 2018/12/27 17:30 by djearthquake