RPI4 Ethernet port not working

1st Official Post

    My Rpi4 refuses to turn the ethernet port with a 50ft long plus cable connection, but it does work with a short ethernet cable when tested to the same netgear switch, all other devices connect fine too. After some digging it looks like there is a problem with the ethernet driver and updating it fixes the low power issue on the port. My problem is I can't figure out how to update just the ethernet drivers. I have automatic updates on and currently on version 9.2.5

    You could try the nightly build which runs a significantly newer kernel. It'll also give you some new features like high bitrate audio passthrough, although you may also find glitches or bugs (such as the inability to use the UI to connect to wifi).

    • Official Post

    If the nightly built doesn't work, consider to buy an Ethernet to WiFi adapter. Because it's Ethernet-based, you will have no driver problems. Those adapter usually have 2.4 GHz only, not 5 GHz. If you can live with that, this could be your solution.

    Quote from Da Flex

    If the nightly built doesn't work, consider to buy an Ethernet to WiFi adapter. Because it's Ethernet-based, you will have no driver problems. Those adapter usually have 2.4 GHz only, not 5 GHz. If you can live with that, this could be your solution.

    The wifi does work, but I'm having buffer issues, if I'm hardwired, it works fine. That being said, my wifi access point is business class, I use an Aerohive AP wired to my Router. I do have a USB to ethernet adapter, but I really want that onboard port to work...my OCD will not allow any other solution..

    I found this info on ethernet cables :

    For Ethernet copper cabling when used for 10/100/1000 BASE-T, the maximum allowed length of a Cat 5e / Cat 6 cable is 100 meters (328 ft). This consists of 90 meters (295 ft) of solid "horizontal" cabling between the patch panel and the wall jack, plus 10 meters (33 ft) of stranded patch cable between each jack and the attached device.

    It must be 100m (328ft) or less in length to be certified. It is possible a longer cable will work, but it is not guaranteed. Shorter Cat 5 cables may also not work if there is a lot of Electromagnetic interference (EMI). Signal attenuation appears to be the limiting factor, too much signal loss and you can't guarantee 100 megabits per second.

    My advice is to try another ethernet cable - maybe one that has better shielding

    Quote from blueribb

    I found this info on ethernet cables :

    For Ethernet copper cabling when used for 10/100/1000 BASE-T, the maximum allowed length of a Cat 5e / Cat 6 cable is 100 meters (328 ft). This consists of 90 meters (295 ft) of solid "horizontal" cabling between the patch panel and the wall jack, plus 10 meters (33 ft) of stranded patch cable between each jack and the attached device.

    It must be 100m (328ft) or less in length to be certified. It is possible a longer cable will work, but it is not guaranteed. Shorter Cat 5 cables may also not work if there is a lot of Electromagnetic interference (EMI). Signal attenuation appears to be the limiting factor, too much signal loss and you can't guarantee 100 megabits per second.

    My advice is to try another ethernet cable - maybe one that has better shielding

    Thanks. My cable is approx 60ft, high quality cat 6. I also tested with several cables of various length, same issue, short cables work, 50ft cables don't. RPI3 works no problem....I'm going to try a Millhouse build and see what that does.

    • Official Post
    Quote from LibreINtoronto

    The wifi does work, but I'm having buffer issues, if I'm hardwired, it works fine. That being said, my wifi access point is business class, I use an Aerohive AP wired to my Router. I do have a USB to ethernet adapter, but I really want that onboard port to work...my OCD will not allow any other solution..

    I'm using a long Ethernet cable, too (around 40 feet), and it's working fine on my RPi 3B+. Maybe it helps to replace the cable, and use one with better shielding.

    PS: After reading your latest post, your cable is probably OK. I don't think RPi 3 and RPi 4 use different Ethernet drivers. I suggest to use a stronger PSU, which will provide more power to the Ethernet port.

    Quote from Da Flex

    PS: After reading your latest post, your cable is probably OK. I don't think RPi 3 and RPi 4 use different Ethernet drivers. I suggest to use a stronger PSU, which will provide more power to the Ethernet port.

    I'm not sure about drivers but they are different hardware. 3B has 100Mbit network whereas 4 has 1Gbit network. So the 4 could very well be more sensitive to a defective cable than the 3 given it'll negotiate at higher speeds, but I would expect since it is different hardware that it would also be different drivers.

    If I have some time today I will try 9.2.5 and the nightly with a 75ft cable just to see if there's any performance differences.