Comment # 6 on bug 1180971 from Hans Braun

I had the same problem: after updating to 5.3.18-lp152.60-default, the display
showed "out of specifications".
This could be overcome in analogy to Bug 1177384:
Log-in via console from a different machine and 
executing the following 4 commands

% mkdir /lib/modules/5.3.18-lp152.60-default/extra
% cp
/lib/modules/5.3.18-lp152.57-default/kernel/drivers/gpu/drm/radeon/radeon.ko
/lib/modules/5.3.18-lp152.60-default/extra/
% depmod 5.3.18-lp152.60-default
% mkinitrd

("%" is a replacement for my command prompt)

Hope this helps - H.Braun