How To Install Kernel 6.15 RC6 On Ubuntu, Debian And Derivative Systems

The Linux kernel is the core component of any Linux operating system, managing hardware resources and system processes.

Installing the latest Linux kernel release candidate, like Kernel 6.15 RC6, can help you test new features and improvements ahead of the stable release. Whether you’re a developer, sysadmin, or just an enthusiast, having control over your kernel is a powerful tool—especially when combined with advanced command-line techniques. If you’re comfortable using tools like ps and grep for process inspection, you might find this useful trick helpful when managing system processes during kernel testing.

The latest version available is Kernel 6.15 RC6, which has been recently released.

The official announcement:

“Everything still looks fairly normal – we’ve got a bit more commits than we did in rc5, which isn’t the trend I want to see as the release progresses, but the difference isn’t all that big and it feels more like just the normal noise in timing fluctuation in pull requests of fixes than any real signal.

So I won’t worry about it. We’ve got another two weeks to go in the normal release schedule, and it still feels like everything is on track.”

Main highlights of Kernel 6.15 RC6

AMD CPU Performance Fix
A significant performance issue affecting recent AMD processors (Zen 4 and Zen 5) has been resolved. The kernel was unnecessarily applying virtualization-related mitigations even when no virtual machines were running, leading to reduced performance. With this update, those mitigations are now only applied when virtualization is actively used.

Memory Management Bug Fix
A bug in the memory management subsystem on x86 architectures, introduced in December, has been fixed. It involved scenarios where TLB (Translation Lookaside Buffer) flushes could be skipped during memory context switches. The fix ensures that flushes are properly enforced, improving system stability and security.

Improved Game Controller Support
The XPad driver now supports several new game controllers, including the HORI Drum controller, PowerA Fusion Pro 4, 8BitDo Ultimate 3-mode controller, Hyperkin DuchesS Xbox One controller, and the PowerA MOGA XP-Ultra. There’s also improved handling of the “Share” button on supported devices.

Touchpad Enhancements
Changes have been made for better Synaptics touchpad support on laptops from Dynabook, TUXEDO, Dell, and HP. These devices now use SMBus mode instead of PS/2, resulting in more reliable and responsive touchpad behavior.

Filesystem Improvements
Updates to Btrfs, OCFS2, and EROFS bring increased stability, bug fixes, and better handling of compressed files. These improvements contribute to more efficient and resilient storage performance.

KVM Virtualization Updates
The KVM subsystem has received enhancements aimed at improving virtualization performance, especially on ARM-based systems.

In this article I will show you how to install Kernel 6.15 RC6 on Ubuntu, Linux Mint and derivative systems.

Check your current kernel version:

Before proceeding with the installation, verify your current kernel version by running:

uname -r

How to install Kernel 6.15 RC6 on Ubuntu, Linux Mint, Debian, and derivative systems (amd64/x86_64):

Step 1: Update Your System

Run the following commands to ensure your system is up to date:

sudo apt update && sudo apt upgrade -y

This will update your package list and upgrade all installed packages to their latest versions.

• What Does apt update Do?
  This command updates the package list to reflect the latest versions available from your repositories.
• What Does apt upgrade Do?
  It upgrades all the packages that have new versions available while keeping existing dependencies intact.

Step 2: Download the Kernel 6.15 RC6 Packages

Download the necessary kernel packages from the official Ubuntu repositories or the kernel website:

wget -c https://kernel.ubuntu.com/mainline/v6.15-rc6/amd64/linux-headers-6.15.0-061500rc6-generic_6.15.0-061500rc6.202505112238_amd64.deb
wget -c https://kernel.ubuntu.com/mainline/v6.15-rc6/amd64/linux-headers-6.15.0-061500rc6_6.15.0-061500rc6.202505112238_all.deb
wget -c https://kernel.ubuntu.com/mainline/v6.15-rc6/amd64/linux-image-unsigned-6.15.0-061500rc6-generic_6.15.0-061500rc6.202505112238_amd64.deb
wget -c https://kernel.ubuntu.com/mainline/v6.15-rc6/amd64/linux-modules-6.15.0-061500rc6-generic_6.15.0-061500rc6.202505112238_amd64.deb

Step 3: Install the New Kernel

Install the downloaded packages using dpkg:

sudo dpkg -i linux-headers-6.15*.deb linux-modules-6.15*.deb linux-image-6.15*.deb

Step 4: Update GRUB and Reboot

Once the kernel installation is complete, update GRUB to ensure the new kernel is recognized:

Regenerate the GRUB Configuration

Run the following command to update GRUB with the latest installed kernel:

sudo update-grub

Verify GRUB Configuration

To confirm that the new kernel has been detected, check the GRUB configuration:

cat /boot/grub/grub.cfg | grep 'menuentry'

This should list all available kernels, including Kernel 6.15 RC6.

Reboot the System

Restart your computer to apply the changes:

sudo reboot

• Select the New Kernel (if needed) – If the system doesn’t automatically boot into the new kernel, you can manually select it:
  • Hold Shift or Esc during boot to access the GRUB menu.
  • Navigate to Advanced options for Ubuntu.
  • Choose the entry with Kernel 6.15 RC6.
  • Press Enter to boot.

Verifying the Installed Kernel

After rebooting, confirm the new kernel version:

uname -r

Rolling Back to a Previous Kernel

If you encounter issues with the new kernel, you can revert to an older version:

• Reboot and Access the GRUB Menu – Restart your system and hold Shift or Esc to enter the GRUB boot menu.
• Select Advanced options for Ubuntu – Choose an older kernel version and boot into it.
• Remove Kernel 6.15 RC3 – If you prefer to remove the new kernel permanently, run:

sudo apt remove linux-headers-6.15* linux-modules-6.15* linux-image-6.15*
sudo update-grub

Conclusion

In conclusion, Linux 6.15 RC6 delivers important performance fixes, particularly for AMD systems, along with enhanced hardware support and stability improvements across the board. With the final release approaching, this RC shows promising refinements for both everyday users and developers.

These updates reflect the kernel community’s ongoing focus on both performance and hardware compatibility. Whether you’re testing on cutting-edge hardware or managing virtualized environments, Linux 6.15 RC6 offers meaningful improvements that enhance reliability and usability across a wide range of systems.