You are my hero, fegol
Thank you very very much.
I leave here the (easy) steps that I have followed in case they are useful for someone with CoreELEC.
My steps with CoreELEC 19.5 rc2 (S905X3 device):
1) I have upgraded CoreELEC tvheadend addon with yours:
https://www.linuxsat-support.com/cms/attachment/208297-19-5-zip/
I used:
service.tvheadend43-19.5.105.zip
included in your 19.5.zip pack.
Additional considerations:
When upgrading the tvheadend addon with yours, the contents of the "bin" and "picons" folders are deleted or modified. I made a backup of these folders (bin, picons) before updating the tvheadend addon to restore the grabbers I had configured in "bin", and the picons in "picons" after the upgrade.
2) I'm using "normal" oscam from entware:
Index of /aarch64-k3.10/
(at this moment, "normal" version 11711).
Works perfectly well. No need of modified oscam with your tvheadend addon.
In oscam.conf:
[dvbapi]
enabled = 1
pmt_mode = 4
listen_port = 9090
user = (the user that you configure in tvheadend / CA)
read_sdt = 2
write_sdt_prov = 1
boxtype = pc
Thanks again. The CoreELEC tvheadend modified addon has been really very useful for me.