Unexpected boot menu option on RHEL 9

2 min read 26-10-2024

the ifix

When working with Red Hat Enterprise Linux (RHEL) 9, you might encounter an unexpected boot menu option that can confuse users or disrupt workflows. This article will help clarify this issue, provide insights into its causes, and guide you through possible resolutions.

The Problem Scenario

Imagine booting your RHEL 9 system only to be greeted by an unfamiliar boot menu option that seems out of place. Instead of the usual boot entries, there's an unexpected choice that you didn't configure or expect. This can be quite alarming, especially if you rely on a particular configuration for your system.

Original Code for the Problem

Here's an example scenario that illustrates the problem when inspecting the boot entries in RHEL 9:

# Viewing current boot menu options
sudo efibootmgr -v

This command might output something like this:

BootCurrent: 0001
Timeout: 2 seconds
BootOrder: 0001,0002,0003,0004
Boot0001* RHEL 9
Boot0002* Windows Boot Manager
Boot0003* UEFI Shell
Boot0004* Another Linux Distribution

In this output, the entry "UEFI Shell" is unexpected and may not have been configured by the user.

Analysis of the Issue

The appearance of unexpected boot options can often be attributed to several factors:

Multiple Installations: If you have multiple operating systems installed, especially in a dual or multi-boot setup, they can occasionally alter the boot order or introduce new menu options.
Boot Loader Configuration: Issues with GRUB (the bootloader used by RHEL) configurations can lead to unexpected entries. This is particularly true if installations are made or partitions are modified without properly updating GRUB.
Firmware Updates: Sometimes, updates to UEFI firmware can change the boot order or introduce new boot options that were not previously present.
Corrupted Boot Configuration: Files like /boot/grub2/grub.cfg might become corrupted, causing unexpected behavior.

Practical Example: Resolving the Issue

To resolve the problem, you can take several steps:

Check Boot Order: Use the efibootmgr command to inspect your boot order and identify the unexpected entries. If you want to remove an unwanted entry, you can do so with:
```
sudo efibootmgr -b 0003 -B
```
This command removes the "UEFI Shell" entry.
Update GRUB Configuration: If you suspect the GRUB configuration is incorrect, you can regenerate it using:
```
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
```
Review UEFI Settings: If your firmware settings are outdated, consider updating them to ensure that they reflect your current system configuration properly.
Reinstall GRUB: If the problem persists, reinstalling the GRUB bootloader may help restore expected behavior:
```
sudo grub2-install /dev/sda
```
Make sure to replace /dev/sda with the appropriate disk.

Conclusion

Encountering unexpected boot menu options on RHEL 9 can be perplexing but is often manageable through careful inspection and configuration of your system. Whether you are dealing with a dual-boot setup or have made recent changes to your system, understanding the underlying causes can facilitate effective troubleshooting.

Additional Resources

This article aims to empower you with the knowledge to handle unexpected boot menu options on RHEL 9 efficiently, enhancing your overall system management skills. If you encounter additional issues or have questions, don't hesitate to seek help from community forums or official support channels.