My tests with v4l-updatelee were not sucesfull.
Crazycat’s pull an update some days ago.
If your receiver is reported as loaded in dmesg, there should be no reason for tvheadend not recognizing-it.
For solving that problem in my system, i’ve inserted a small change in tvheadend.service, to wait for every /dev/dvb/adapter frontend loaded in the system after an initial 10 seconds delay.
Edit /lib/systemd/system/tvheadend.service and add ExecStartPre:
ExecStartPre=/bin/bash -c "sleep 10; for adapter in /dev/dvb/*; do COUNT=60; echo tvheadend testing $adapter; while [[ $COUNT -gt 0 ]]; do [[ -e $adapter/frontend0 ]] && COUNT=1; ((COUNT--)); sleep 1; done; done"