Radxa Dual 2.5G Router HAT

Overview

The Radxa Dual 2.5G Router HAT is designed for the ROCK series and Raspberry Pi 5. It provides high-performance networking and storage expansion through the PCIe interface. Key features include:

• Two 2.5GbE Ethernet ports for high-speed and stable networking
• NVMe SSD storage expansion via an M.2 M Key connector
• Additional PCIe expansion via an FPC connector

This HAT is ideal for networking applications and high-performance storage solutions, significantly extending the capabilities of your single-board computer.

Compatible SBCs

The Radxa Dual 2.5G Router HAT currently supports the following single-board computers:

• ROCK 2A / 2F
• ROCK 4D
• ROCK 5C
• Raspberry Pi 5

Features

• 2 x 2.5GbE Ethernet ports for high-speed networking
• 1 x M.2 M Key connector with PCIe 3.0/2.0 1-lane for NVMe SSD
• 1 x FPC connector with PCIe 3.0/2.0 1-lane for additional expansion
• 1 x 12 V DC jack (5.5 mm outer diameter / 2.5 mm inner diameter)

Specifications

Item	Specification
Ethernet controller	Realtek RTL8125B
Ethernet speed	2 x 2.5GbE
PCIe	PCIe 3.0/2.0 1-lane
Storage	M.2 M Key 2280 NVMe SSD
Power input	12 V DC (5.5/2.5 mm jack)
Form factor	HAT-compatible

Package contents

• 1 x Radxa Dual 2.5G Router HAT
• 4 x standoffs
• 8 x screws (for securing the HAT and SSD)
• 1 x heatsink (for cooling the Ethernet controller)
• 1 x adapter board (for connecting to compatible SBCs)
• 1 x connection cable

Board layout

40-pin header pinout

Description	Function	Pin #	Pin #	Function	Description
Not used		1	2	VCC	5 V
Not used		3	4	VCC	5 V
Not used		5	6	GND	Ground
Not used		7	8	Not used
Ground	GND	9	10	Not used
Not used		11	12	Not used
Not used		13	14	GND	Ground
Not used		15	16	GPIO	FPC power (controls FPC power)
Not used		17	18	Not used
Not used		19	20	GND	Ground
Not used		21	22	Not used
Not used		23	24	Not used
Ground	GND	25	26	Not used
EEPROM I2C	I2C_SDA	27	28	I2C_SCL	EEPROM I2C
Not used		29	30	GND	Ground
Not used		31	32	Not used
Not used		33	34	GND	Ground
Not used		35	36	Not used
Not used		37	38	Not used
Ground	GND	39	40	Not used

Installation

Install on ROCK series boards

1. Power off your SBC completely.
2. Install the standoffs on the SBC.
3. Connect the adapter board to the SBC PCIe interface.
4. Align the Dual 2.5G Router HAT with the 40-pin header and standoffs.
5. Secure the HAT using the provided screws.
6. If you use an NVMe SSD, install it into the M.2 slot and secure it with a screw.
7. Connect a 12 V power supply to the DC jack.
8. Power on the SBC.

Install on Raspberry Pi 5

1. Power off your Raspberry Pi 5 completely.
2. Connect the adapter board to the Raspberry Pi 5 PCIe interface.
3. Align the Dual 2.5G Router HAT with the 40-pin header.
4. Secure the HAT using the provided standoffs and screws.
5. If you use an NVMe SSD, install it into the M.2 slot and secure it with a screw.
6. Connect a 12 V power supply to the DC jack.
7. Power on the Raspberry Pi 5.

Software configuration

Network setup

The Ethernet ports typically appear as additional network interfaces (for example, eth1 and eth2). You can configure them with standard Linux networking tools.

Example configuration:

# List available interfaces
ip addr

# Configure a static IP for eth1
sudo ip addr add 192.168.1.100/24 dev eth1
sudo ip link set eth1 up

# Request an IP address via DHCP for eth2
sudo dhclient eth2

NVMe SSD setup

After installing an NVMe SSD, you can format and mount it using standard Linux commands:

# Check whether the SSD is detected
lsblk

# Format the SSD (replace nvme0n1 with your device)
sudo mkfs.ext4 /dev/nvme0n1

# Mount the SSD
sudo mkdir -p /mnt/ssd
sudo mount /dev/nvme0n1 /mnt/ssd

Troubleshooting

Common issues

1. Ethernet ports are not detected

   • Make sure the HAT is properly connected to the PCIe interface
   • Check that the 12 V power supply is connected and working
   • Verify that your Linux kernel supports the RTL8125B controller

2. NVMe SSD is not detected

   • Make sure the SSD is properly seated in the M.2 slot
   • Try a different SSD to rule out compatibility issues
   • Check PCIe-related kernel logs: dmesg | grep -i pcie

3. Poor network performance

   • Update to the latest OS and Linux kernel version
   • Check network cabling (use Cat5e or better for 2.5GbE)
   • Make sure the connected network equipment supports 2.5GbE

Use cases

The Radxa Dual 2.5G Router HAT is well suited for:

• Building a high-performance router or firewall
• Network-attached storage (NAS) with fast networking
• Edge computing workloads that require high data throughput
• Home lab servers that need multiple network interfaces
• Media servers with fast networking and storage