@Syntox Thanks! It should support SMB1, do you have an error message?
Mounting SMB to the HA Media Browser is complicated through an external extension as mounts can’t be propagated from one container to the other (as far as I know). What you can do however is execute a script at boot that mounts the smb share.
For that, you need to create a custom shell command in the configuration.yaml, and a script to call it. The script will call it in the homeassistant container, so files will be available in the HA media browser but not in other extensions (reason why I put a smb mount on each of my addons!). Please find all information here in this thread : Mount remote smb share on hassio
An alternative is to use this addon (that I haven’t used yet) that executes the same command automatically in the homeassistant container : Run On Startup.d - Home Assistant OS - Home Assistant Community (home-assistant.io)