I updated my kernel. However, problems have arisen after that. So I started to download multiple kernels and install them through
sudo dpkg -i *.deb
I thought that at any time, the kernel was changing. However, among all version, my computer still see the latest version. All my installed kernels are now:
ii linux-image-5.3.0-18-generic 5.3.0-18.19+1 amd64 Signed kernel image generic
ii linux-image-5.3.0-40-generic 5.3.0-40.32 amd64 Signed kernel image generic
ii linux-image-generic 5.3.0.40.34 amd64 Generic Linux kernel image
ii linux-image-unsigned-5.6.0-050600rc3-lowlatency 5.6.0-050600rc3.202002240232 amd64 Linux kernel image for version 5.6.0 on 64 bit x86 SMP
ii linux-image-unsigned-5.6.0-050600rc4-lowlatency 5.6.0-050600rc4.202003012332 amd64 Linux kernel image for version 5.6.0 on 64 bit x86 SMP
ii linux-image-unsigned-5.6.0-050600rc5-lowlatency 5.6.0-050600rc5.202003082130 amd64 Linux kernel image for version 5.6.0 on 64 bit x86 SMP
The one used by my acutal Ubuntu is the last one. How can I select a different version to run?
update-grub
after installing those kernel packages? Also, those look like unsigned kernels - did you remember to disable Secure Boot?