How to Install OpenWrt on Plusnet Hub One Router

The Plusnet Hub One router is quite good hardware but the official firmware restricts what you can do. For example, you can’t setup a VPN or monitor traffic. This tutorial will show you how to flash the device with OpenWrt Version 21.02 so that you can get the most out of the device.

Table of Contents

• Tools and Software Required
• Step 1: Open the Plusnet Hub One case
• Step 2: Solder Wires to Circuit Board
• Step 3: Connect Wires to USB to Serial TTL Dongle
• Step 4: Configure Network and TFTP Server
• Step 5: Boot router in CFG 04 mode.
• Step 6: Load UART u-boot
• Step 7: Load Install Image from TFTP Server
• Step 8: Mount USB Flash Drive
• Step 9: Backup Existing Firmware
• Step 10: Prepare System and Install OpenWrt Firmware

Tools and Software Required

Flashing the Plusnet Hub One Router with OpenWrt is done by connecting a computer to the router over a serial communication. However, the router doesn’t have a serial port and requires wires soldered to the circuit board.

I used this Soldering Iron Kit* and this USB to Serial TTL Dongle* to connect my MacBook Pro to the router.

You also need a USB Flash Drive* to store the OpenWrt Firmware on. This drive is connected to the router during the installation process and it’s also used to backup the existing stock firmware.

Software and OpenWrt Firmware

Depending on what operating system you are using, you will need to install a terminal emulation program that supports serial communication. Since I’m using a MacBook Pro, this guide uses picocom which can be installed with homebrew.

We also need to download the following software.

• BTHOMEHUBV5A UART u-boot (allows booting via serial console)
• BTHOMEHUBV5A Install Image (booted via TFTP)
• OpenWrt 21.02 Firmware

Once you’ve downloaded the OpenWrt Firmware, copy it onto a FAT32 or exFAT formatted USB Flash Drive* and plug it into the USB port of the router.

Step 1: Open the Plusnet Hub One case

The first thing we need to do is open the case. It’s held together with clips and there are no screws. Read the following tutorial to learn where the clips are and how to open the case without damaging them.

How to Open the Plusnet Case.

Step 2: Solder Wires to Circuit Board

The next thing we need to do is locate the solder pads for the serial port GND, TX and RX connections and solder wires to them. We also need to locate the boot selector (BOOT_SEL) pad and either solder a wire to it or touch a wire onto it while powering on the router.

The image below shows the locations of the pads.

Now we need to solder wires to them. In the image below, I’ve soldered wires to all the pads but it might be better not to solder the BOOT_SEL wire to the board. The reason for this, is because some people have experienced routers getting stuck in boot CFG mode, which might be caused by too much heat or damage to the resistor.

Once you’ve soldered the wires, strip the ends and connect them to the USB to Serial TTL Dongle*. The TX on the router goes to the RX on the dongle.

Step 3: Configure Network and TFTP Server

Now you need to setup a TFTP Server on your network and configure the IP address as 192.169.1.2. Since I’m using a Mac that has a built in TFTP server, I assigned a static IP of 192.169.1.2 and enabled the server with the following commands.

sudo launchctl load -F /System/Library/LaunchDaemons/tftp.plist
sudo launchctl start com.apple.tftpd

Copy the BTHOMEHUBV5A install Image to the root of the server. In my case that is /private/tftpboot.

Connect the router to the TFTP server either directly or via a switch on your network and then we can boot the install image over the network.

Step 4: Open Serial Port Connection

At a terminal run the following command to initiate a serial connection.

picocom -b 115200 /dev/tty.usbserial-008B6F4B --send-cmd="cat"

The address of the TTL dongle will be different for you, depending on what machine you are using to connect. On Linux it’s probably /dev/ttyUSB0.

Step 5: Boot router in CFG 04 mode

Once you’re connected to the serial port, we are ready to power on the router. Before press the power button, you need to connect the BOOT_SEL wire to GND then immediately release it after powering on the device.

If you connected successfully, you should see CFG 04 in the terminal output.

Step 6: Load UART u-boot

Open a new Terminal and run the following command to boot the custom U-boot loader.

cat lede-lantiq-bthomehubv5a_ram-u-boot.asc > /dev/tty.usbserial-008B6F4B 

Step 7: Load Install Image from TFTP Server

Once the U-boot loader has loaded, you should be able to run commands in the original terminal window. The command we need to run is the tftpboot command. This will download the install image from the TFTP server, which contains the utilities required flash the firmware.

Run the following command to start boot the install image.

tftpboot 0x81000000 lede-lantiq-xrx200-BTHOMEHUBV5A-installimage.bin; bootm 0x81000000

Note: by default the IP address of the router is 192.168.1.1 and this might already be in use on your network. You can change the router IP by running.

editenv ipaddr

Then changing the address.

Step 8: Mount USB Flash Drive

Make sure the USB Flash Drive is plugged onto the router then run the following commands to mount it.

mkdir /tmp/mounts/media
mount /dev/sda1 /tmp/mounts/media

Step 9: Backup Existing Firmware

Once the USB Flash Drive is mounted, run the following command to backup the existing firmware.

nanddump --file /tmp/mounts/media/hh5a.nanddump /dev/mtd4

Wait for the data to be copied. This will take quite a while so go and make a drink and be patient for the command to finish.

root@lede:/tmp# nanddump --file /tmp/mounts/media/hh5a.nanddump /dev/mtd4
ECC failed: 0
ECC corrected: 0
Number of bad blocks: 0
Number of bbt blocks: 4
Block size 131072, page size 2048, OOB size 64
Dumping data starting at 0x00000000 and ending at 0x08000000...

Step 10: Prepare System and Install OpenWrt Firmware

Run the prepare command to start the flashing process.

prepare

Type in YESIHAVEABACKUP then press Return.

Choose device type a for BT and b for Plusnet.

Now run the following command to flash the firmware.

sysupgrade /tmp/mounts/media/openwrt-21.02.0-lantiq-xrx200-bt_homehub-v5a-squashfs-sysupgrade.bin

Wait for the install process to finish and the router to reboot into CFG 04 mode. Once more power cycle and it should boot into the OpenWrt system.

BusyBox v1.33.1 (2021-08-31 22:20:08 UTC) built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 -----------------------------------------------------
 OpenWrt 21.02.0, r16279-5cc0535800
 -----------------------------------------------------
root@openwrt:~# 

That’s it, you can now disconnect the serial port wires, tape them up and tidy them neatly inside the router before putting the case back on.

You can now configure the router how you see fit. For much more details, read this OpenWrt Installation and Configuration Guide.

Conclusion

In this tutorial, you learned how to flash the Plusnet Hub One Router with OpenWrt Version 21.02. You can now do things like:

• Configure VPNs.
• Setup VLANs.
• Block Ads and websites at the router.
• Enable QoS.
• Setup and File or Printer Server via the USB port.

And pretty much anything you can do with Linux.