Widemac SL-R720X / XDX-RN502J

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.

This is a white-label mass-market ralink-based router produced by Bococom, selling under the Widemac SL-R720X label. The device is sometimes also referred to as XDX-RN502J, a string that appears prominently on the PCB board. Some of the devices ship with OpenWrt preinstalled.

Please check out the article flash.layout. It contains an example and a couple of explanations.

On this device, flash layout is the following:

0x000000000000-0x000000030000 “u-boot”
0x000000030000-0x000000040000 “u-boot-env”
0x000000040000-0x000000050000 “factory”
0x000000050000-0x000000150000 “kernel”
0x000000150000-0x000000400000 “rootfs”

auto-created partitions at boot:

  • mtd: partition “rootfs” set to be root filesystem
  • mtd: partition “rootfs_data” created automatically, ofs=2E0000, len=120000
0x0000002e0000-0x000000400000 “rootfs_data”
0x000000050000-0x000000400000 “firmware”

OpenWrt was installed with the serial port and tftp method. There is currently no known way to flash directly from the built-in firmware. So, follow generic.flashing.tftp for general setup of a tftp server and firmware to load. Use the sysupgrade image. Set your terminal to 57600 bauds, 8,N, 1. At boot, you will see the following on your serial terminal:

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. 9: Load Boot Loader code then write to Flash via TFTP.

choose 2, then answer the prompts. Note that option 1 does not work with the sysupgrade image; booting will fail on finding the root partition.

After installation, copy-paste the following configuration into /etc/config/network

config interface 'loopback'
      option ifname 'lo'
      option proto 'static'
      option ipaddr '127.0.0.1'
      option netmask '255.0.0.0'

config globals 'globals'
      option ula_prefix 'fd37:bd9a:2b09::/48'

config switch 'switch0'
      option enable '1'
      option enable_vlan '1'
      option reset '1'

config switch_vlan
      option vlan '1'
      option device 'switch0'
      option ports '0 6t'

config switch_vlan
      option vlan '2'
      option device 'switch0'
      option ports '1 2 3 4 6t'

config switch_port                                         
      option port '0'
      option pvid '1'

config interface 'lan'
      option force_link '1'
      option type 'bridge'
      option proto 'static'
      option ipaddr '192.168.1.1'
      option netmask '255.255.255.0'
      option ip6assign '60'
      option _orig_ifname 'eth0.2 wlan0'
      option _orig_bridge 'true'
      option ifname 'eth0.2'
      option nat '1'

config interface 'wan'
      option proto 'dhcp'
      option _orig_ifname 'eth0.1'
      option _orig_bridge 'false'
      option ifname 'eth0.1'
      option broadcast '1'

Reboot, and the network ports should be operational.

WARNING: The current OpenWrt image does not contain a valid configuration for the various wired network ports
on the device. As a result, wired networking broken until copy-pasting in the above configuration.

generic.sysupgrade

If you have already installed OpenWrt and like to reflash for e.g. upgrading to a new OpenWrt version you can upgrade using the mtd command line tool. It is important that you put the firmware image into the ramdisk (/tmp) before you start flashing.

LuCI Web Upgrade Process

Terminal Upgrade Process

  • Login as root via SSH on 192.168.1.1
  • Use the following commands to upgrade.
cd /tmp/
wget http://downloads.openwrt.org/snapshots/trunk/XXX/xxx.abc
sysupgrade /tmp/xxx.abc
  • If sysupgrade does not support this router, use the following commands.
cd /tmp/
wget http://downloads.openwrt.org/snapshots/trunk/XXX/xxx.abc
mtd write /tmp/xxx.abc linux && reboot

Basic configuration After flashing, proceed with this.
Set up your Internet connection, configure wireless, configure USB port, etc.

hardware.button on howto use and configure the hardware button(s).

The SL-R720X devices has one button. In the original configuration it resets the router when pressed for 5 seconds and switches WPS mode when pressed for only 1 second.

BUTTON Event
1 sec WPS
5 sec reset

The default network configuration is:

Interface Name Description Default configuration
br-lan LAN & WiFi 192.168.1.1/24
vlan0 (eth0.1) LAN ports (1 to 4) None
vlan1 (eth0.2) WAN port DHCP
wl0 WiFi Disabled

Numbers 1-4 are ports 1-4 as labeled on the unit, number 0 is the Internet (WAN) on the unit, 6 is the internal connection to the router itself. vlan0 = eth0.0, vlan1 = eth0.1 and so on.

Port Switch port
0 Internet (WAN)
1 LAN 1
2 LAN 2
3 LAN 3
4 LAN 4
5 non-connected?
6 CPU (internal)
Architecture MIPS
Vendor Ralink
bootloader U-Boot
System-On-Chip RT3052
CPU/Speed 24Kc 384 MHz
Flash-Chip 29LV320DBTI-70G/ST 25P64V6P
Flash size 4096 KiB
RAM 32 MiB
Wireless rt2872 2.4GHz 802.11bgn
Ethernet ?
USB Yes 1 x 2.0
GPIO Yes 6 free
Serial Yes
JTAG No

Model Number / Backside label
Insert picture

Case Front:
Insert picture

Case Back:
Insert picture

Note: This will void your warranty!

  • To remove the cover just unscrew the four corner phillips screws under the rubber feet.

PCB Top

PCB bottom

The serial port is on the unpopulated header labelled “console”/“J2”. Pins are, from the pin closest to J2 Gnd, Rx, Tx, Vcc. Use a 5V ↔ 3.3V level shifter. Some of the boards are shipped with a populated header. Use 57600 8N1, hard & soft flow control OFF.

Insert photo of PCB with markings

This website uses cookies. By using the website, you agree with storing cookies on your computer. Also you acknowledge that you have read and understand our Privacy Policy. If you do not agree leave the website.More information about cookies
  • Last modified: 2024/02/12 08:58
  • by 127.0.0.1