kylinV10SP2系统执行了一下yum update结果把内核更新了，导致系统启动默认使用了新的内核，结果卡到系统开机界面进不到系统里。
先手动选择默认内核进入系统，然后修改系统默认启动内核：
查看当前内核版本：
[root@xdsdcdsd ~]# uname -r
4.19.90-24.4.v2101.ky10.x86_64
查看启动界面有哪些可选项
[root@xdsdcdsd ~]# awk -F\' '$1=="menuentry " {print i++ " : " $2}' /boot/efi/EFI/kylin/grub.cfg
0 : Kylin Linux Advanced Server (4.19.90-25.42.v2101.ky10.x86_64) V10 (Sword)
1 : Kylin Linux Advanced Server (4.19.90-24.4.v2101.ky10.x86_64) V10 (Sword)
{spa.pet-planett.com]
{spa.vpinggu.com]
{spa.xhcbcq.com]
{spa.ljyjzc.com]
{spa.one-blank.com]
{spa.assurmli.com]
{spa.cdsjlyyp.com]
2 : Kylin Linux Advanced Server (0-rescue-292ffa61afcb4b96a0cec1133c69a8a2) V10 (Sword)
3 : System setup
查看系统当前开机默认加载哪个引导项
[root@xdsdcdsd ~]# grub2-editenv list
saved_entry=Kylin Linux Advanced Server (4.19.90-25.42.v2101.ky10.x86_64) V10 (Sword)
boot_success=0
修改默认启动内核：切换成24.4
[root@xdsdcdsd ~]# grub2-set-default "Kylin Linux Advanced Server (4.19.90-24.4.v2101.ky10.x86_64) V10 (Sword)"
[root@xdsdcdsd ~]# grub2-editenv list
saved_entry=Kylin Linux Advanced Server (4.19.90-24.4.v2101.ky10.x86_64) V10 (Sword)
boot_success=0
