Hey there,
Am currently using rpi2 and rpi3 with LEv.7.0.3, installing the linuxserver repo seems to be possible only if downloading the .zip file and then manually installing it.
So far if trying the update the LibreELEC Add-ons repo it says it's up to date.
Repo shows up on LE8 alpha and betas but not 7. You're right the zip installs on 7. The reason we limited the repo to 8 is because 7 doesn't have docker support on the aarch64 platform
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I'm on generic.Btw I installed the repo and plex by manually downloading the repo zip. Plex shows as installed. But I can't access the web interface. Don't know where to start looking. Same with portainer. Nothing at <my-ip-address>:9000
Hmm. In command line can you try the following commands and check their output?
docker ps -a
docker images
systemctl status docker.linuxserver.portainer
The first one should list all containers created and their running status
The second will list all docker images downloaded (shows if there is a connection issue to docker hub)
The third should show the status of the systemd file created by the portainer addon and if it failed, why it failed (my guess is that you may be out of space, in which case you can delete some containers with docker rm containername and you can get the container name from the first command above)