I found this solution accidentally and it works for me every time if the signal lock isn’t present during boot. Also, it can be used to fix the intermittent signal lock and the of signal lock while restarting services (i.e. librarian). -not tested 100%
Solution (please note that this is not a professional solution)
Just remove the F-connector from the HDStar tuner and reconnect it again. While reconnecting the connector, you can see some blue color electric sparks around the outer surface of the connector. Also, you can see the HDStar’s green led turns to the red and indicates the signal lock. Also, the tuner settings section in the librarian interface gets updated immediately and shows ‘receiving’.
However, this could be a rare case and probably there’s a power related issue behind this. Or while reconnecting the F-connector, some kind of signal will force the kernel to restore the signal lock. This is just my idea and I’m not an linux/electronics expert.
If anyone can recreate this test, please update this thread.