So a little update.
I left the Raspberry on during the night. This morning, there is still no web interface available. Still the Raspberry seems to be connected with the router though, I managed to retrieve the IP adress. I both tried the hassio.local link and the internal IP adress, both with the 8123 port.
Does anyone have any ideas about what to try next? Can’t be this hard to install this software, right?!
Same issue here with a slight twist. I was able to setup and use HA for several hours. I walked away for 30 min and came back and I get site cannot be reached at http://hassio.local:8123/ the following repeated output from the Pi 3B+:
This occurred after I tried to setup the configurator with no success.
Any updates on this issue?
Yesterday I discovered this topic about someone needing to restart his router. I tried that, but without success.
I can’t believe that nobody seems to know a solution. Is there any way to look into log files with SSH to get more information about what’s going on?
I opened the SD card on my computer to take a look. It seems to be different from the examples I see in youtube installation tutorials. Does anyone know if this is right?
I figured it out. I tried installing raspbian stretch lite on my Pi 3B+:
Then I followed these instructions:
The webinterface was loaded without any trouble.
Okay, so I managed to get Home Assistant working at my Raspberry Pi 3B+. At least I thought. Turns out there are differences between the hassos image and the manual installation of Home Assistant:
If you don’t install the image, you won’t get the hass.io menu item. Without that item it’s not possible to install third party addons. At least not the easy way…
I’m going back to the image, hoping it will work soon…
i did manage to get further without the ipv6 link is not ready error
i prept a usb stick with the network info seen as in
https://github.com/home-assistant/hassos/blob/dev/Documentation/network.md
so now it boots without the ipv6 error and i see that the raspberry pi is actually connected through wifi as well.
before i only the lan connection was visible.
and now i probably have to wait till hassio is updated before i can login to the page:8123
im gona leave it for now an see if it later on its working.
Ureka!!! for me any way. yesterday i changed the dns servers in my router because i couldnt update docker containers on my unraid server.
so i thought maybe that also works for homeassistant. i tried it yesterdat with the already running install but no go. so today i flashed the latest .img again and i saw :8123 port straight from the first scan. and when i tried to go to it in browser the update messages appeared. so now the thing is running again.
i used the cloudflare dns before but now i have opendns en google put in my router.
maybe this helps for any one else with this problem.
Has anyone been able to truly solve this issue. I just purchased a pi3+ specifically to get into HA and im getting this exact issue. When it first boots on the screen it states no network found. Then goes through the loading of line codes.
Ive tried a config file… I have wifi and hardwired connections i see them both in my router that they are connected. So i know thats working. Its just getting it passed this first part.
Also having this issue. If someone has fixed this, step by step would be great 
Yet another here, having the same issue on a brand new Pi 3B+. Just sits there with this wlan0: link not ready message.
New flash of the 32bit image. No custom network config file. Plugged in via ethernet with a DHCP router on the network.
Tried multiple power supplies, multiple SD Cards, multiple ethernet cables, custom network config files both in WLAN and Ethernet static mode, tried the 64bit image too. Nothing works. Never even hits the DHCP when in ethernet mode.
This sounds like an inherent issue with the B+. Any devs out there care to weigh in?
About to throw this thing in the bin after about 10 hours of troubleshooting! 
Ok after a number of hours of further mucking around… I’ve got it to start up successfuly.
Here are the steps I took:
The console scrolled through for 397 seconds before it was contactable on http://ipaddress:8123, the final lines shown in the console were:
[358.571] IPv6: ADDRCONF (NETDEV U_UP): wlan0: link is not ready
[358.578] brcmfmac: power management disabled
[397.048] udevd[7]: starting version 3.2.5
[397.098] udevd[8]: starting endev-3.2.5
[674.588] IPv6: ADDRCONF (NETDEV U_UP): wlan0: link is not ready
[674.598] brcmfmac: power management disabled
[990.590] IPv6: ADDRCONF (NETDEV U_UP): wlan0: link is not ready
[990.592] brcmfmac: power management disabled
It looks like the wlan0: link is not ready lines just repeat over and over when you’re not using wlan. It’s not an error, and the system is operating normally.
I was expecting some kind of final message saying “Hass.io UP/Online”. I was maybe giving up on it too soon.
Anyways, I decided to write this out in detail to help others who might be struggling, and because I wish I had this info myself before I messed around with it for 12 hours! Hope this helps!
I had all these issues also, going around in circles.
Success in the end.
issue was with using not pad to copy and paste the code to the my-network file for the usb stick t get the IV4 wifi enabled.
downloaded and used notepad++ for windows
copied and pasted code as instructed in the hassio instructions
formatted the code to ANCI and line indented for UNIX
all in the menu in note pad ++
remember to remove the TXT extension on the file when saving in the network folder
USB volume name CONFIG
Install the usb stick before powering up the PI
worked first time after 2 days of chasing my tail.
.
That might be something I’m going to try.
I finally got Hassio working by sticking with the ethernet cable and not doing any custom network config at all. An ethernet cable is more stable anyway.
Of course there needs to be some configuration in the router as well.
If you don’t use the network file to connect to wifi and just stick with the ethernet cable, not being able to connect to hassio has to be caused by router settings. You should at least check the assigned internal IP address and port as mentioned above.
By the way. I recommend you all to setup a backup system immediately after installing. I recently lost a lot of work by getting a corrupted installation. Making snapshots stores the backup files on the same SD card as hassio is installed on. I wasn’t able to retrieve them. So, store them online (cloud) or on another harddrive! Reference: Connection refused after restoring backup, no errors, samba working
IPv6: ADDCONF (NETDEV_UP): wlan0: link is not ready
brcmfmac: power management disabled
These are not errors. Both messages are present on a working install.
They continue to be posted by people who aren’t familiar with the logs as a reference to a problem. Then similar minded people search for it and find these threads and this becomes kind of a loop.
IPV6 for wlan0 (wireless connection) is never going to be ready.
Power management for wifi is indeed disabled. Again, you would see these messages on a normal working install.
Your installs may be having a problem pulling down the Home Assistant image from docker hub because of some networking issue. Sometimes DNS is the problem. Sometimes the time (ntp) servers are not being reached or are otherwise blocked and the time is wrong. If the time of the device doesn’t match the time of the server where the images are downloaded from, the request will be rejected.
There is a console.
You hit enter at the os log screen, then enter root to get to the Hassio cli. The Hassio cli has limited custom commands for checking Home Assistant itself. If Home Assistant isn’t running these aren’t going to be much help. So, from the Hassio cli you enter login to reach the host.
From the host ( # ) you can use commands like docker ps to see whether you have both running containers: supervisor and homeassistant. You might be missing the homeassistant container if a connection could not be made.
You can also enter nmcli to check that your ethernet has an ip address. If you see an ip address, you should be good. Enter http://that_ip_address_you_see:8123 in a browser from a device on the same network.
I’m not a dev or even very smart but I’ve set up Hassio many many many times.
My advice:
Done all of the above suggested by moderator - can see that dockers are running, using cli. Can see preparing hass.io page in browser. However ‘wlan0 link is not ready brcmfmac power management disabled’ message keeps on reappearing in host. Have been waiting more than 30 minutes for download to complete. What else can I do to get home assistant running in browser properly?
trying to get hass.io running on RPI3 with 32 bit image, using ethernet. unfortunately, still no luck after 8 hours - same power management disabled message appears. Is this really not indicator for an error? Nothing else happens. ‘preparing hass.io screen’ still in browser. Any help would be appreciated with this.
Finally got it working properly - disabled IPV6 on router and that immediately fixed the problem. Login screen is displayed in browser now.
After getting hass.io running on RPI, configured Z-wave USB key by using /dev/ttys0 as serial port in config file. Now working on getting key to discover z-wave devices …
Can someone please take this feedback, why WIFI configuration is designed to be major pain in the bu**?
Why It has to got though the USB Stick where you need to import something and on the next restart wifi is gone again and you wonder if the import is stored somewhere after reboot or is it wiped … or you are expected to connect with the table every restart to do the import again etc.
Suggestion: Can we design future versions in the way that there is certain config file already present in the image and all you have to do is filling in the blanks for the Wifi network name and password.
P.S. Sorry for bit of frustration, but trying to follow all these guides is very misleading and after spending hours you will get after restart still
wlan0: link is not ready
Hi
Thx a lot.
This solved the issue for me when booting over the USB WIFI confic File, with the suggested parameters in the manual.