# How set kernel on boot for R9.2?

**URL:** <https://forums.rockylinux.org/t/how-set-kernel-on-boot-for-r9-2/15570>\
**Category:** Rocky Linux Help & Support\
**Created:** [August 22, 2024, 10:43pm UTC](https://forums.rockylinux.org/t/how-set-kernel-on-boot-for-r9-2/15570 "2024-08-22T22:43:10Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![lerroot](https://avatars.discourse-cdn.com/v4/letter/l/d26b3c/32.png) [@lerroot](https://forums.rockylinux.org/u/lerroot)\
**Post date:** [August 22, 2024, 10:43pm UTC](https://forums.rockylinux.org/t/how-set-kernel-on-boot-for-r9-2/15570/1 "2024-08-22T22:43:10Z")

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Hi-

I installed KDE and it forced a new kernel install. I want to revert to the older kernel. Uninstalling KDE did not work.

[root@host ~]# uname -a  
Linux [host.domain.com](http://host.domain.com) 5.14.0-427.31.1.el9\_4.x86\_64 #1 SMP PREEMPT\_DYNAMIC Wed Aug 14 16:15:25 UTC 2024 x86\_64 x86\_64 x86\_64 GNU/Linux

[root@host ~]# rpm -q kernel  
kernel-5.14.0-284.11.1.el9\_2.x86\_64  
kernel-5.14.0-284.30.1.el9\_2.x86\_64

[root@host ~]# dnf list --showduplicates kernel  
Last metadata expiration check: 2:55:01 ago on Thu 22 Aug 2024 12:45:30 PM PDT.  
Installed Packages  
kernel.x86\_64 5.14.0-284.11.1.el9\_2 @anaconda  
kernel.x86\_64 5.14.0-284.30.1.el9\_2 @@commandline  
Available Packages  
kernel.x86\_64 5.14.0-427.31.1.el9\_4 baseos

Why is 5.14.0-427.31.1.el9\_4.x86\_64 reflected in uname if it is not installed? How do I select 5.14.0-284.30.1.el9\_2 as the boot kernel? Thank you.

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<div class="post-metadata">

**Author:** ![lerroot](https://avatars.discourse-cdn.com/v4/letter/l/d26b3c/32.png) [@lerroot](https://forums.rockylinux.org/u/lerroot)\
**Post date:** [August 22, 2024, 10:58pm UTC](https://forums.rockylinux.org/t/how-set-kernel-on-boot-for-r9-2/15570/2 "2024-08-22T22:58:53Z")

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I used infos here:

> **[Chapter 2. Specifying the RHEL kernel to run | Red Hat Product...](https://docs.redhat.com/en/documentation/red_hat_enterprise_linux_for_real_time/9/html/installing_rhel_9_for_real_time/assembly_specifying-the-kernel-to-run_installing-rhel-9-for-real-time#configuring-kernel-rt-as-the-default-boot-kernel_assembly_specifying-the-kernel-to-run)**
>
> Chapter 2. Specifying the RHEL kernel to run | Red Hat Documentation

and ran:  
grubby --set-default=/boot/vmlinuz-5.14.0-284.30.1.el9\_2.x86\_64

looks good! please let me know if i missed anything. thank you.

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**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\
**Post date:** [August 23, 2024, 6:08am UTC](https://forums.rockylinux.org/t/how-set-kernel-on-boot-for-r9-2/15570/3 "2024-08-23T06:08:40Z")

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> [@lerroot](#):
>
> Why is 5.14.0-427.31.1.el9\_4.x86\_64 reflected in uname if it is not installed?

Because ‘kernel’ is not everything. In fact, it is very little:

```bash
$ dnf -q rq -l kernel-5.14.0-427.31.1.el9_4.x86_64
Package kernel-5.14.0-427.31.1.el9_4.x86_64 contains no files

$ dnf -q rq --requires --resolve kernel-5.14.0-427.31.1.el9_4.x86_64
kernel-core-0:5.14.0-427.31.1.el9_4.x86_64
kernel-modules-0:5.14.0-427.31.1.el9_4.x86_64
kernel-modules-core-0:5.14.0-427.31.1.el9_4.x86_64

```

So what does?

```auto
rpm -qa kernel\*
dnf list kernel\*
dnf rq --installonly

```

* * *

You did set the default entry “in the GRUB” menu that GRUB chooses on boot. For now.  
The install of each new kernel(-core) will change that. See `/etc/sysconfig/kernel`

* * *

Kernel 5.14.0-427.31.1.el9\_4 contains many **security** and bug fixes and new features that the 5.14.0-284.30.1.el9\_2 do not have nor never will.

There will be no fixes for el9\_2. el9\_4 _is_ the fix (until el9\_5 is released). Rocky supports only latest – currently el9\_4 based versions of packages.

If updated application packages start to require newer kernel – like the KDE did – and _truly_ require, then you can’t install/update those either. Particularly GRUB on systems that use Secure Boot belong to that category.

* * *

“Want” is an unspecific, weak requirement. Is there a real, concrete, technical reason why use of supported version of Rocky is not possible for you?

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**Author:** ![system](https://us1.discourse-cdn.com/flex020/uploads/rockylinux/original/1X/91b7219eec10e30013422e4df76c1d898711a5d5.svg) [@system](https://forums.rockylinux.org/u/system)\
**Post date:** [October 22, 2024, 6:08am UTC](https://forums.rockylinux.org/t/how-set-kernel-on-boot-for-r9-2/15570/4 "2024-10-22T06:08:49Z")

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