How To Install Kernel 6.15 RC3 On Ubuntu, Debian And Derivative Systems

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

The latest version available is Kernel 6.15 RC3, which has been recently released.

Main highlights:

Core Kernel and Architecture Enhancements

GCC 15 Compatibility: Resolved compilation issues with GCC 15, ensuring smoother builds with the latest compiler versions.
Intel Bartlett Lake Support: Introduced support for Intel’s upcoming Bartlett Lake processors, preparing the kernel for next-generation hardware.
AMD Zen 5 Microcode Checks: Added microcode verification for AMD Zen 5 CPUs, enhancing system stability and security.

Graphics and Hardware Improvements

DRM Updates: Integrated numerous enhancements to the Direct Rendering Manager (DRM), including support for new GPUs and performance optimizations.
Dell/Alienware Thermal Control: Expanded thermal management support for Dell and Alienware devices, improving hardware compatibility.
Apple Z2 Touchscreen/Touch Bar Driver: Introduced a new driver for Apple’s Z2 Touchscreen and Touch Bar, enhancing support for Apple hardware.

File System and Storage Developments

Large Atomic Write Preparations: Implemented foundational changes in the Virtual File System (VFS) to support large atomic writes, benefiting file systems like XFS and EXT4.
Compressed VHD Image Detection: Improved detection mechanisms for compressed Virtual Hard Disk (VHD) images that may exceed the target drive’s capacity.

Security and Stability Fixes

Side-Loading Vulnerability Patch: Addressed a side-loading vulnerability (CVE-2025-26624) related to cfgmgr32.dll, enhancing system security.
UI Memory Leak Fixes: Resolved memory leaks in the user interface, contributing to overall system stability.
Command-Line Hogger Adjustment: Fixed issues with the command-line hogger not being deleted when running Rufus from a different directory.

Additional Updates

Ztsd Compression Support: Added support for ztsd compression in disk images, offering better handling of compressed files.
GPT GUID Exclusion Feature: Introduced a new setting to ignore disks with specific GPT GUIDs, reducing the risk of accidental overwrites.
Locale Fallback Enhancement: Improved error description retrieval by falling back to user/system default locales.

In this article I will show you how to install Kernel 6.15 RC3 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 RC3 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 RC3 Packages

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

wget -c https://kernel.ubuntu.com/mainline/v6.15-rc3/amd64/linux-headers-6.15.0-061500rc3-generic_6.15.0-061500rc3.202504202138_amd64.deb
wget -c https://kernel.ubuntu.com/mainline/v6.15-rc3/amd64/linux-headers-6.15.0-061500rc3_6.15.0-061500rc3.202504202138_all.deb
wget -c https://kernel.ubuntu.com/mainline/v6.15-rc3/amd64/linux-image-unsigned-6.15.0-061500rc3-generic_6.15.0-061500rc3.202504202138_amd64.deb
wget -c https://kernel.ubuntu.com/mainline/v6.15-rc3/amd64/linux-modules-6.15.0-061500rc3-generic_6.15.0-061500rc3.202504202138_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 RC3.

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 RC3.
- 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

Linux 6.15-rc3 shows that the kernel development team is pushing forward with both strong hardware support and important internal improvements. With better compatibility for upcoming Intel and AMD CPUs, enhancements in GPU support, and updates to core filesystem operations, this release candidate ensures that Linux remains ready for the next generation of devices and workloads.Security, stability, and performance remain top priorities, as seen with the fixes for vulnerabilities, memory leaks, and better handling of compressed disk images. As Linux 6.15 continues to mature, users and developers alike can look forward to a more polished and reliable experience once the final release arrives.