After removing/reinserting USB stick here are the last linse from dmesg:
[ 4800.718349] em2874 #0: Identified as KWorld USB ATSC TV Stick UB435-Q V3 (card=93)
[ 4800.718360] em2874 #0: dvb set to bulk mode.
[ 4800.718463] em2874 #0: Binding DVB extension
[ 4800.736802] tda18212 1-0060: NXP TDA18212HN/M successfully identified
[ 4800.736834] DVB: registering new adapter (em2874 #0)
[ 4800.736844] usb 1-2.2: DVB: registering adapter 0 frontend 0 (LG Electronics LGDT3305 VSB/QAM Frontend)…
[ 4800.738363] em2874 #0: DVB extension successfully initialized
The kernel is:
Linux 4.9.113-45-osmc aarch64
I also ran
sudo apt-get install firmware-linux-nonfree
but the USB stick still didn’t appear in TV Headend. Now that I removed/reinstalled the USB stick it does show up in TV Headend