LucyRTL8125Ethernet Issue

[Dornila]

Hey!

So, I decided to try installing macOS 26.2, and it worked successfully. I didn't have internet access in recovery mode, so I decided to deal with it later and built an offilne installer. Everything works fine, but I still don't have internet. I found several reports online about the LucyRTL8125Ethernet kext not working properly on macOS 26, and I have no idea what to do. I've tried almost everything - disabling the IOMMU, changing the device properties, messing around with kernel settings but nothing has helped. The kext works fine for some people, but that's not the case for me.

I'm happy to hear any suggestions for fixing this!

My PC specs:

CPU: Ryzen 7 9800X3D
MB: ASRock B650E PG Riptide WiFi
GPU: Sapphire Pulse RX6600

 

[Edhawk]

Might be related to the version of the Realtek 2.5Gb Ethernet controller your motherboard uses. Older/first Gen Realtek 2.5Gb controllers work perfectly well with the kext. I have 3 x 500 series motherboards and 5 x PCIe adapters that use the first Gen controller and they all work as expected in Sequoia and Tahoe.

Some controllers named ‘Dragon’ are known to be problematic when used in macOS. Even though they have the same vendor and device ID’s as the first Gen devices. Could be related to the sub-device ID?

 

[Dornila]

Might be related to the version of the Realtek 2.5Gb Ethernet controller your motherboard uses. Older/first Gen Realtek 2.5Gb controllers work perfectly well with the kext. I have 3 x 500 series motherboards and 5 x PCIe adapters that use the first Gen controller and they all work as expected in Sequoia and Tahoe.

Some controllers named ‘Dragon’ are known to be problematic when used in macOS. Even though they have the same vendor and device ID’s as the first Gen devices. Could be related to the sub-device ID?

I forgot to say that I had macOS Ventura and Sonoma and the internet was fine, that was a year or two ago, I changed a lot in my computer but the MB remained the same. I even remember what base I used - here it is: https://forum.amd-osx.com/threads/r...staller-freezes-at-12-minutes-remaining.4691/

I spent more than 20 hours trying to fix the problem and still have to use HoRNDIS

 

[Edhawk]

The specification page for your ASRock motherboard says it contains a Killer E3100G Ethernet controller.

https://pg.asrock.com/mb/AMD/B650E%20PG%20Riptide%20WiFi/index.asp#Specification

While this is an Ethernet offering from Intel it appears to have a Realtek controller. Are you using the latest kext from Mieze’s GitHub repository?

Release LucyRTL8125-V1.2.2 · Mieze/LucyRTL8125Ethernet

Fixed IOFree() bug.

github.com

There might be some information regarding the Killer series of controllers in the later stages of this support thread over at InsanelyMac.

LucyRTL8125Ethernet.kext for Realtek RTL8125

This project is dedicated to Lucy, my lovely little Tyrannofelis Rex. LucyRTL8125Ethernet is an open source driver for the Realtek RTL8125 family of 2.5GBit Ethernet controllers. Key Features of the Driver Supports all versions of Realtek's RTL8125 2.5GBit Ethernet Controllers found on recent boa...

www.insanelymac.com

 

[Dornila]

The specification page for your ASRock motherboard says it contains a Killer E3100G Ethernet controller.

https://pg.asrock.com/mb/AMD/B650E%20PG%20Riptide%20WiFi/index.asp#Specification

While this is an Ethernet offering from Intel it appears to have a Realtek controller. Are you using the latest kext from Mieze’s GitHub repository?

Release LucyRTL8125-V1.2.2 · Mieze/LucyRTL8125Ethernet

Fixed IOFree() bug.

github.com

There might be some information regarding the Killer series of controllers in the later stages of this support thread over at InsanelyMac.

LucyRTL8125Ethernet.kext for Realtek RTL8125

This project is dedicated to Lucy, my lovely little Tyrannofelis Rex. LucyRTL8125Ethernet is an open source driver for the Realtek RTL8125 family of 2.5GBit Ethernet controllers. Key Features of the Driver Supports all versions of Realtek's RTL8125 2.5GBit Ethernet Controllers found on recent boa...

www.insanelymac.com

Hi Edhawk, thanks for the reply.

You are right, it is indeed a Killer E3100G.
I am using the latest LucyRTL8125Ethernet 1.2.2 (Release).

The problem is that the kext does not natively recognize this chip on my setup (I saw "Unsupported chip found" in logs initially).
I tried to manually inject the original Realtek device-id (0x8125) via DeviceProperties to force the driver to load.

The result:
The driver attaches successfully (ioreg shows LucyRTL8125 is active and registered), BUT the interface is never created.
Looking at ioreg, the driver seems stuck:

• IOLinkSpeed = 0
• IOLinkStatus = 0
• IOActiveMedium is empty

It seems like the driver cannot initialize the PHY or negotiate the link speed on macOS 26, even when forced to load.

Has anyone successfully used the E3100G variant on Tahoe? Or does it require a specific patch for the new kernel?

 

[Edhawk]

Not me, but I have used the Realtek 2.5Gb (8125B) Ethernet port on my Asus B550m system in Tahoe. Just while installing and configuring Tahoe, until I could set up and enable my Aquantia 10Gb PCIe adapter.

 

[Astral420]

This is quite interesting as I struggled getting my RTL8125B from loading in Tahoe. Not sure if it'll work, but you can try blocking appleethernetrl in kernel as a holy mary alongside injecting it inside deviceproperties as well or resetting interfaces.