Tried to create: /vendor/oem/modem-config/S461.1/modem.conf
And put inside these lines, one by one and then reboot, then next one… (the third and fourth are based in what I see in other modem.conf files, trying to guess):
mcfg_sw/generic/EU/Telefonica/Commercial/Spain/mcfg_sw.mbn
mcfg_sw/generic/EU/Telefonica/NONIMS/Spain/mcfg_sw.mbn
mcfg_sw/generic/euro/telefonica/commercial/esp/mcfg_sw.mbn
mcfg_sw/generic/euro/telefonica/non_ims/esp/mcfg_sw.mbn
No sucess, and no useful info got with: journalctl -t ofonod -f