Petatel PSR-680W

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.

Wireless CDMA 450 MHz Router

CPU Ram Flash Internet WiFi Ethernet USB Serial JTag RUIM card
Ralink RT3052 32MiB 4MiB EV-DO Rev.A 450MHz 11 bgn 4 x 1 No Yes No Yes

Specific Howtos

Firmware image is obtained by compiling source from the latest development branch (trunk)

If you use LuCI, you may want to install following packages before compiling

./scripts/feeds install luci
./scripts/feeds install luci-proto-ppp
./scripts/feeds install luci-proto-3g

When performing “make menuconfig” select


If you use LuCI, additionally select


To install OpenWrt for the first time on a router with factory firmware you will need OpenWrt image in the standard “uImage” format. To compile such image, when performing “make menuconfig” select Target Images - ramdisk


After OpenWrt is successfully installed, it is recommended to perform sysupgrade to squashfs firmware. To compile such image, when performing “make menuconfig” select Target Images - squashfs


Specific Howtos

In PSR-680W factory firmware the bootloader menu is disabled.
Fortunately, bootloader contains TFTP client which is enabled by default and can be used for firmware upload.
The bootloader TFTP client expects firmware in the standard “uImage” format with file name “rt305x_image.bin”.
Install TFTP server software on your PC, and give your PC static IP address with network mask
Make sure the firmware file is “uImage” type, is renamed to rt305x_image.bin, and is located in the directory which TFTP server uses to upload files.
Connect your PC with the router using Ethernet cable.
Power cycle the router. You may have to repeat power off-on cycle several times till you see that file transfer is actually taking place.

PSR-680W with OpenWrt firmware installed has following flash layout:

6 cmdlinepart partitions found on MTD device physmap-flash.0
Creating 6 MTD partitions on "physmap-flash.0":
0x000000000000-0x000000030000 : "u-boot"
0x000000030000-0x000000040000 : "u-boot-env"
0x000000040000-0x000000050000 : "factory"
0x000000050000-0x000000130000 : "kernel"
0x000000130000-0x000000400000 : "rootfs"
mtd: partition "rootfs" set to be root filesystem
mtd: partition "rootfs_data" created automatically, ofs=2F0000, len=110000
0x0000002f0000-0x000000400000 : "rootfs_data"
0x000000050000-0x000000400000 : "firmware"


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
  • Use the following commands to upgrade.
cd /tmp/
sysupgrade /tmp/

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

When OpenWrt is installed, by default there is no network interface for CDMA and Wi-Fi is disabled.

To add CDMA interface using LuCI:

  • Go to Network - Interfaces - Add new interface...
  • On the General Setup tab select:
Modem device /dev/ttyACM0
Service Type EV-DO
PAP/CHAP username Provided by your network operator
PAP/CHAP password Provided by your network operator
  • On the Firewall Settings tab select “wan”.

Resulting configuration may look like this:


To enable Wi-Fi using LuCI:

  • Go to Network - Wifi and press Enable.

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

The Petatel PSR-680W has one “Reset” button at the bottom. Here, we merely name the button, so we can use it in the above Howto:

Reset reset
Architecture: Ralink
bootloader: U-Boot
System-On-Chip: Ralink RT3052 SoC
Flash-Chip: NOR SAMSUNG K8P3215UQB
Flash size: 4 MiB
RAM: 32 MiB
Wireless: 2.4GHz 802.11bgn
Ethernet: 1 WAN port and 4 LAN ports 10/100Mbps
Internet: EVDO Rev.A 450 MHz (Internal Qualcomm MSM6800A mini PCI express module)
Serial: Yes

port.serial general information about the serial port, serial port cable, etc.

How to connect to the Serial Port of this specific device:

Serial console is the 4-pin header on the upper side of the board marked as “J10”.
Device case should be opened to access the pins.
The pins are marked as “GND, RX, TX, 3.3V”.
Actually, the pins are GND, TX, RX, V3.3 (TX pin sending signal from the router to the PC).
The voltage is 3.3V TTL.
Baud rate is 115200.

On device side, there are two serial ports which show up as following device nodes:
/dev/ttyS0 (UARTF) is used for communication with CDMA module using vendor-specific AT commands.
/dev/ttyS1 (UARTL) is used for the console.

For some Help with the Tags, please have a look here: tags

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  • Last modified: 2024/02/12 08:58
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