本文参考：马春杰杰的博客
想切换不同系统内核怎么办？按下面步骤即可：
1 安装指定版本的Ubuntu 的内核：
从 /~kernel-ppa/mainline/中选择需要的版本：
根据你的系统架构下载 *.deb 文件：
wget /~kernel-ppa/mainline/v5.4.180/amd64/linux-headers-5.4.180-0504180_5.4.180-0504180.202202161239_all.deb
wget /~kernel-ppa/mainline/v5.4.180/amd64/linux-headers-5.4.180-0504180-generic_5.4.180-0504180.202202161239_amd64.deb
wget /~kernel-ppa/mainline/v5.4.180/amd64/linux-image-unsigned-5.4.180-0504180-generic_5.4.180-0504180.202202161239_amd64.deb
安装*.deb：
sudo dpkg -i *.deb
更新grub:
sudo update-grub
2 确定当前使用的内核id：
grep submenu /boot/grub/
如下：
submenu 'Ubuntu 高级选项' $menuentry_id_option 'gnulinux-advanced-3f5e97d5-cd08-4560-94df-613149aac32e' {
将单引号中的id记录下来gnulinux-advanced-3f5e97d5-cd08-4560-94df-613149aac32e。
3 查找想要使用的内核id ：
grep gnulinux /boot/grub/
set default="gnulinux-advanced-3f5e97d5-cd08-4560-94df-613149aac32e>gnulinux-4.4.248-0404248-generic-advanced-3f5e97d5-cd08-4560-94df-613149aac32e"
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-3f5e97d5-cd08-4560-94df-613149aac32e' {
submenu 'Ubuntu 高级选项' $menuentry_id_option 'gnulinux-advanced-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu，Linux 4.15.1-041501-lowlatency' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.1-041501-lowlatency-advanced-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.15.1-041501-lowlatency (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.1-041501-lowlatency-init-upstart-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.15.1-041501-lowlatency (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.1-041501-lowlatency-recovery-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu，Linux 4.15.1-041501-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.1-041501-generic-advanced-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.15.1-041501-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.1-041501-generic-init-upstart-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.15.1-041501-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.1-041501-generic-recovery-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu，Linux 4.4.248-0404248-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.248-0404248-generic-advanced-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.4.248-0404248-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.248-0404248-generic-init-upstart-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.4.248-0404248-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.248-0404248-generic-recovery-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu，Linux 4.4.0-141-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-141-generic-advanced-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.4.0-141-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-141-generic-init-upstart-3f5e97d5-cd08-4560-94df-613149aac32e' {
menuentry 'Ubuntu, with Linux 4.4.0-141-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-141-generic-recovery-3f5e97d5-cd08-4560-94df-613149aac32e' {
选择我们想要切换的内核，这里我选择的为：gnulinux-4.4.248-0404248-generic-advanced-3f5e97d5-cd08-4560-94df-613149aac32e
4 修改grub文件，切换内核：
vim /etc/default/grub
根据第二步和第三步得到的内核:
将
GRUB_DEFAULT=0
改为:
GRUB_DEFAULT="gnulinux-advanced-3f5e97d5-cd08-4560-94df-613149aac32e>gnulinux-4.4.248-0404248-generic-advanced-3f5e97d5-cd08-4560-94df-613149aac32e"
5 更新grub：
sudo update-grub
6 重启
查看系统内核版本：
uname -r
7 安装指定内核版本其他方法
参考之前的帖子：Ubuntu安装指定版本的内核