Hell Hans, I have the exact same issue with the same version. What exact package and what version was updated that fixed the issue for you? I am getting a seg fault on Buster aswell after configuration is set.
ii gnuradio 3.7.12.0-2 amd64 ii gqrx-sdr 2.9-2+b2 amd64 The GQRX version has not changed since December 2017 gqrx-sdr (2.9-2) unstable; urgency=medium * upstream Debian patches, update to v2.9-4-g4138038 -- A. Maitland Bottoms <bott...@debian.org> Sun, 10 Dec 2017 16:53:16 -0500 -- Regards Martin Naughton