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Cinebot Mini/Max — Ubuntu RT Kernel Upgrade

DANGEROUS CONFIRMED CINEBOT MINI CINEBOT MAX FLAIR 7

Summary

Cinebot Mini and Cinebot Max run on a Linux PC controller. Flair requires a real-time (RT) kernel to perform motion control — the standard Ubuntu generic kernel is not suitable. When you upgrade Ubuntu from 22.04 to 24.04, or when Ubuntu automatically updates the kernel, you must make sure the system boots into the correct real-time kernel and not the generic one.

This guide covers:

  1. Upgrading Ubuntu from 22.04 to 24.04
  2. Installing the real-time kernel using the MRMC update script
  3. What to do if Ubuntu installs kernel 6.14 and breaks real-time boot

Do not attempt on a production system without time to spare

This procedure modifies the operating system kernel and bootloader configuration. If done incorrectly the controller will not boot into Flair. Do not attempt this the day before a shoot. Allow time to troubleshoot and, if necessary, restore the system. Have the MRMC support contact available: support@mrmoco.com

Why the RT Kernel Is Required

Standard Linux kernels (generic kernel) are not suitable for real-time motion control. The real-time (PREEMPT_RT) kernel provides the low-latency scheduling that Flair needs to maintain accurate axis timing and move profiles.

If Flair starts with the wrong (generic) kernel, it will alert you with this message:

"If you are not using the real time kernel, Flair will alert you"

The Flair alert screen indicates the currently running kernel is not the real-time version. Motion control will not function correctly until you boot into the correct kernel.

When You Need This

  • You are upgrading a Cinebot Mini or Max controller from Ubuntu 22.04 to Ubuntu 24.04
  • Ubuntu has auto-updated the kernel from 6.11-rt to 6.14 (generic) and Flair is now showing the real-time kernel alert
  • You are setting up a fresh Cinebot Mini or Max controller

Download

The upgrade package contains the kernel update scripts and configuration files referenced in this procedure.

Download CinebotMiniMax-ControllerUpgrade.zip

The zip is approximately 1.5 GB and includes all required files to complete the upgrade.

Also see the official MRMC procedure document:

Cinebot Mini/Max — Ubuntu & RT Kernel Upgrade Procedure (full step-by-step guide)

Procedure

Connect your monitor and keyboard BEFORE powering on

The Cinebot Mini/Max controller PC detects displays at boot time. If you plug a monitor in after the machine is already running, you will get a blank screen. Connect your monitor, keyboard, and mouse to the controller PC first, then power it on.

Part 1 — Upgrade Ubuntu from 22.04 to 24.04

  1. Check your current Ubuntu version. Go to Settings > About. It should show Ubuntu 22.04.
  2. Launch Software Updater from the Applications menu (bottom left of the taskbar).
  3. Ubuntu 24.04 will appear as an available upgrade. Click Upgrade, then click Upgrade again on the confirmation prompt.
  4. The upgrade will start and may take 30–60 minutes. During the process:
  5. If prompted to keep or replace customised configurations — select KEEP.
  6. If prompted about the grub file — select "keep the local version currently installed" and click Next.
  7. When prompted, remove obsolete packages.
  8. Once the upgrade completes, restart the laptop or PC.

Part 2 — Install the Real-Time Kernel

After rebooting into Ubuntu 24.04:

  1. Locate the downloaded upgrade package. Extract CinebotMiniMax-ControllerUpgrade.zip and copy the files to Home > setup-files, confirming any overwrite prompts.
  2. Open a Terminal inside the setup-files folder: right-click the folder and select Open in Terminal.

  3. Make the update script executable:

    chmod +x update-kernel.sh

  4. Run the kernel update script. For kernel 6.8:

    sudo ./update-kernel.sh 6.8

    When prompted for the password, enter: mrmc1234

  5. After the script completes, verify the RT kernel was installed correctly. In the same terminal, run:

    uname -r

    The output should contain rt in the kernel version string (e.g. 6.11.0-rt). If it shows a generic kernel without rt, the RT kernel has not yet been set as the default.

Part 3 — Verify Flair Starts Correctly

After rebooting, start Flair and confirm there is no real-time kernel warning. If Flair starts normally and you can engage the robot, the procedure is complete.

Known Issue: Ubuntu 6.14 Kernel Breaks Real-Time Boot

Ubuntu released a kernel update from 6.11 to 6.14. If you explicitly update your Ubuntu system, it will install the 6.14 generic kernel and set it as the default on startup. This kernel is not real-time and Flair will display a warning alert.

"If you explicitly update your system it will install this newer kernel and set that as the default on start-up. If you are not using the real time kernel, Flair will alert you." — @gordon_admin, MRMC (July 2025)

The Flair team is building and testing a real-time capable 6.14 kernel. Until that is available, you must manually select the 6.11-rt kernel at boot.

Selecting the 6.11-rt kernel via GRUB Advanced Options

This only needs to be done once. GRUB is configured to remember and re-use the last selected option on every subsequent reboot.

  1. Reboot the controller PC.
  2. At the GRUB boot menu, select Advanced Options for Ubuntu.
  3. From the list of kernels, select the one with 6.11 and rt in the name.
  4. Do not select a recovery mode entry.
  5. Do not select a generic (non-rt) kernel.
  6. Look for a string like: Ubuntu, with Linux 6.11.0-rt-amd64
  7. The system will boot into the 6.11-rt kernel. On every subsequent reboot, GRUB will automatically select the same kernel.
  8. Start Flair and confirm no real-time kernel warning appears.

Do not run apt upgrade without checking the kernel

Running sudo apt upgrade or using Software Updater on a Cinebot controller may silently upgrade the default kernel to 6.14. Always check uname -r after any system update and reselect the 6.11-rt kernel via GRUB Advanced Options if needed.

Community Notes

From the Flair Community WhatsApp (February 2025):

"Ubuntu may propose an update to the kernel from 6.8 to 6.11. Please DO NOT UPDATE. The 6.11 kernel will not be real time and that will be a problem. We will have an updated 6.11 real time kernel available later next week." — Gordon Eschke, MRMC

From the official forum post (July 2025):

"Reboot and select Advanced Options for Ubuntu on the boot menu. Select the 6.11 kernel with 'rt' in the string, not recovery mode and not generic. Once that's set, it will continue to select that kernel on reboot." — @gordon_admin

Sources: talk.mrmoco.com topics 1661 and 1842; Flair Community WhatsApp 2024–2025; Cinebot Mini/Max Ubuntu RT Kernel Upgrade Procedure PDF (MRMC)