RTL8125BG (Realtek 2.5GbE) onboard NIC not detected on GMKtec NucBox G10

[hgn32]

Describe the feature

Add r8125 driver support for Realtek RTL8125BG 2.5GbE NIC to the generic-x86-64 kernel build.

The onboard Realtek RTL8125BG 2.5GbE NIC is not detected by HAOS on the GMKtec NucBox G10. The PCI device is visible to the kernel (0000:01:00.0, class 0x020000), but no driver is bound.

Verified PCI information on HAOS 17.1 (kernel 6.12.67-haos):

• vendor: 0x10ec
• device: 0x8125
• subsystem_vendor: 0x10ec
• subsystem_device: 0x8125
• revision: 0x0c ← confirms RTL8125BG (not RTL8125B rev 0x04, nor RTL8125D rev 0x10)

The in-kernel r8169 driver does not bind to this device. The vendor r8125 driver from Realtek resolves the issue on other Linux distributions.

Related: #3880, PR #4014 (added RTL8125D support, but RTL8125BG revision 0x0c remains unhandled)

Use cases

GMKtec NucBox G10 and other mini-PCs with RTL8125BG are popular hardware choices for running HAOS due to their compact size and low power consumption. Without r8125 driver support, the onboard 2.5GbE NIC is completely non-functional, forcing users to use a USB-to-Ethernet adapter as a workaround.

Current workarounds

Using a USB-to-Ethernet adapter. This limits throughput to 1 Gbps and reduces reliability compared to the onboard NIC.

Anything else?

Hardware: GMKtec NucBox G10 (AMD Ryzen 5 3500U / 8125BG)
HAOS version: 17.1
Kernel: 6.12.67-haos
OS Agent: 1.8.1
Installation method: generic-x86-64 (bare metal)