Hello,
I have created a ssd image of homeassistant os using rpi-image. I also download the custom image for raspberry pi 3 from web page. In both cases I get a message “No ethernet” and system enters emergency console.
Thanks for your help.
Did you connect a cable between Pi and a router or hub?
Hi,
To manage expectations, unless you are creating a test environment, or a very modest system, a RPi3b is not a good platform for HASS.
Current HASOS has a realistic minimum requirement of 1Gb of RAM, and really needs 2Gb+. Running on a RPi3A used to work (slowly in 512Mb) with a lot of swapping memory to disk, which will burn a hole in uSD storage. A RPi3B is a bit faster with 1Gb of RAM so can work for some, but you will need patience for some tasks.
HASS installation instructions spell this out: “Raspberry Pi 3 Model B is ok to get started, but the Model A does not have enough RAM”.
I ran a RPI3a many years ago, and later a RPi3b for testing, but with the addition of more integrations and more user-friendly features, HASS has grown in size. Certainly, I’d not attempt ESPhome development on anything less than a RPi4.
Installations with a HAOS image used to be the fabled “plug and play” with wired Ethernet. Both the RPi installer and HASS images should use the same source.
That you’ve seen an error suggests you’ve attached a display and keyboard, although there are a lot of suggestions to try here:
The HASS console is not a standard Linux command line (BASH), so…
I have seen RPi3B with a dead Ethernet port - a useful test would be to try a generic Rasperry Pi OS install on another uSD card to test the hardware, and your LAN / router / DHCP / mDNS. The RPi3B Ethernet LEDs still flashed on a device with failed hardware.
If this helps, 
this post!
Yes, I did connect a cable to a hub. The message “No ethernet” is at the very beginning of the boot process.
Hi,
I have tested the ethernet port with raspibian os and with the same uSD card and it works fine.
The raspberry pi is connected to a screen, so I’m accessing it from itself.
It is a raspberry pi 3B (2015).
Thank you.
Hi,
Good - so it is unlikely to be hardware.
So, what did going through the troubleshooting links show? (this isn;'t magic - we can only see what data you post (ideally in code fences))
ha network info is the most basic command to try - but note it will show both the ‘host’ interface to the LAN (HAOS), and also the virtual router connecting to the virtual machines (HAS itself, running on top of HAOS).
If this helps, this post!
Hi,
After changing the power source, the message “No ethernet” remains but home assistant works. It seems “Home assistant” require more power than raspibian!!!
Thanks to both of you.