TL;DR: How can I remove a manually compiled and installed kernel?
Long version: I have an AMD Epyc 7002 workstation that refuses to suspend with Lubuntu 18.04 (asking here was unsuccessful, too few people have epycs..). Hoping that a more recent kernel could solve the issue, I manually compiled and installed the latest kernel (at the time of writing, 5.4.14), since the most recent apt-installable kernel was 5.3.0, and I heard tha 5.4.x has much better support for AMD stuff.
Unfortunately, that broke my nvidia drivers, and I have not managed to fix this (I'm stuck at 640x480 resolution with 5.4).
Then I just edited grub config to boot with the old 4.15, and tried to install
uswsusp, which does user space suspension. But then, it just builds for the most recent kernel installed (5.4, indeed).
So I just want to get rid of 5.4 and give
uswsusp a try.