i'm in the process of upgrading my home server from centos7 with an elrepo 5.4.6 kernel and working 6981 card. I've used 4.x kernels in the past without issue on centos7 too.
when i upgrade to centos8 (stream release), which ships with a 4.18.0 kernel, i see the card present in 'dmesg | grep dvb', so i drop the .fw firmware file from the latest tbs linux driver pack (dated 2017) into /lib/firmware and i get repeated 'firmware not responding' in dmesg.
the card has been rock solid on centos7 and fine if i boot back into '7 so I'm confident there's something at software level than hardware.
anything i can do to fix, or is it time to look at replacing the hardware since it is starting to date now? Hope not as i want to stick with TBS but also want a DVB-S2 IP tuner.