How to Safely Remove Unwanted Kernels in Manjaro Linux

Why You Might Install an Additional Kernel on Manjaro

Imagine this: you’re a music producer using Harrison Mixbus, a professional DAW (digital audio workstation) that demands low-latency performance for real-time audio processing. Everything is going well until suddenly, you begin experiencing glitches, dropouts, and unpredictable behavior. You try tweaking settings, but nothing seems to work. Frustrated, you do some research and discover that a real-time kernel could help address the issue by prioritizing CPU resources for your audio applications.

So, you decide to install a real-time kernel on your Manjaro GNOME Minimal Edition system to troubleshoot and improve performance. After installing and testing the new kernel, you find that it does not solve the issue. Now, you’re faced with a dilemma: how do you remove the real-time kernel, especially when it’s no longer needed?

In this article, we’ll walk through the process of removing an unwanted kernel from your Manjaro system. Though Manjaro makes installing additional kernels easy, it doesn’t provide an equally simple method to remove them, which can lead to kernel clutter over time. Let’s break this down step-by-step so you can reclaim your system’s efficiency.

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How to Remove an Unwanted Kernel in Manjaro Linux

If you’re using Manjaro or another Arch-based distribution, you might have found that installing additional kernels for troubleshooting or performance improvements is a straightforward process. However, removing them is not as seamless. Fortunately, with a few simple commands, you can clean up your system and ensure you’re only running the kernels you need.

Step 1: Check Installed Kernels

Before you remove anything, it’s important to confirm which kernels are installed on your system. This can be done easily using Manjaro’s Hardware Detection Tool (MHWD).

1. Open a terminal.
2. Run the following command:
   mhwd-kernel -li
   This will list all the installed kernels on your system, including your current one. You’ll see something like:
   Installed kernels:
   • * linux612
   • * linux-rt614
   • * linux615

In this example, you can see that linux-rt614 is the real-time kernel that you might want to remove.

Step 2: Remove the Unwanted Kernel

Now that you know which kernel you want to remove, it’s time to uninstall it. To do this, run the following command in the terminal:

sudo mhwd-kernel -r linux-rt614

Make sure to replace linux-rt614 with the specific version of the kernel you want to remove. Manjaro uses the mhwd-kernel tool for managing kernel installations and removals, and the command above will safely remove the kernel from your system.

Step 3: Clean Up Unnecessary Packages

After you’ve removed the kernel, it’s a good idea to clean up any residual packages associated with it. You can do this by running:

sudo pacman -Rns linux-rt614

This command will remove any orphaned packages and configurations related to the real-time kernel, further tidying up your system.

Step 4: Update GRUB Bootloader

Once you’ve removed the unwanted kernel, you should update the GRUB bootloader to reflect the changes. To do this, run the following:

sudo update-grub

This ensures that the bootloader menu is updated and that the removed kernel won’t appear as an option during boot.

Step 5: Reboot Your System

Finally, to ensure everything is running as expected, reboot your system with the following command:

sudo reboot

When the system reboots, it will automatically use the default kernel (unless you’ve explicitly chosen another one in the GRUB menu).

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Bonus: How to Boot Into a Different Kernel

While we’ve covered removing an unwanted kernel, it’s also useful to know how to boot into a different kernel if needed. Manjaro makes it easy to switch between kernels, which can be useful for troubleshooting or performance testing.

To boot into a different kernel, follow these steps:

1. Reboot your system.
2. During the boot process, press Esc to bring up the GRUB menu.
3. In the GRUB menu, you should see a list of available kernels. Use the arrow keys to select a different kernel (for example, Linux 5.12, Linux 5.14, or Linux-RT).
4. Press Enter to boot into your selected kernel.

If you need to set a specific kernel as the default, you can do so using the grub-customizer tool, but for now, the above steps should be sufficient.

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Conclusion: The Importance of a Tidy System

Now that you know how to remove unwanted kernels from your system, it’s important to remember why this matters. A tidy system is a fast and efficient system. While additional kernels can be helpful for troubleshooting or improving performance in specific use cases (like your DAW), they can also take up valuable disk space and make your boot options cluttered.

By regularly maintaining your kernel list and removing unnecessary kernels, you help keep your system clean, improve boot times, and avoid potential conflicts. This will ensure your Manjaro setup remains optimized and ready for whatever tasks you need it for, whether that’s music production, programming, or everyday tasks.

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If you’ve found this guide helpful, feel free to share it with others who may be struggling with kernel management. Keeping your system running smoothly is just one of the ways you can ensure your Manjaro setup remains efficient and hassle-free!