Posts: 2
Joined: Sun May 31, 2020 10:52 pm

Pi4 no longer auto enabling eth0

Mon Jun 01, 2020 1:00 am

Serious noob, here. That being said, I wasn't messing around with the OS--at least not directly. I am setting up an openHAB system and tried to enable wireless via the openhabian-config utility. Well that didn't work because it never connected with the router. Unfortunately, the wired interface stopped working, too. Re-disabling wireless did not return wired to an operational state. I posted this problem on the openHAB forum since it was caused by an openHAB utility, but one of the regulars on the forum basically told me to "get lost, take your problem to a Raspberry Pi forum." So here I am. This is a new system, so it's running the latest rev of everything. What I *do* know:

I can get the interface up after booting by issuing a "dhcpcd eth0 up" (no idea if that's even the right/accepted way, but it works and I found it by accident...)

After reboot, the interface is down again until I issue the dhcpcd command again.

When I do issue that command it complains that eth0 is invalid before "forking to the background" whereupon the interface comes up and starts working. It complaining tells me I'm doing *something* wrong, but it still works anyway.

I need help getting it to come up normally by itself after a reboot.

Posts: 1372
Joined: Fri Jan 04, 2013 1:57 pm
Location: de_DE

Re: Pi4 no longer auto enabling eth0

Mon Jun 01, 2020 8:40 pm

in case you don't have data stored you will miss on the sd-card yet,
the simplest and fastest way could be re-flashing the raspberry pi OS image to the sd-card.

i guess you disabled one of the services or messed up network settings by accident.
but to figure out, what you disabled/reconfigured could be take some time.
{ I only give negative feedback }
RPi B (256MB), B (512MB), B+, ZeroW; 2B; 3B, 3B+; 4B (4GB)

Posts: 2
Joined: Sun May 31, 2020 10:52 pm

Re: Pi4 no longer auto enabling eth0

Wed Jun 03, 2020 1:48 am

Well, as it turns out, the openHAB configuration tool messes up the etc/network/interfaces file such that dhcpcd service won't start at boot when one tries to configure wlan0 via that tool. Guess what I WON'T be doing... :!:

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