Kernel Management in MiniOS 🔧

🤔 Why Replace the Kernel?

MiniOS comes with a default kernel, but there are several reasons why you might want to replace it:

🔧 Different Debian Kernel Flavours

Debian provides several kernel variants optimized for different use cases:

linux-image-6.12.38+deb13-amd64 - Standard kernel for 64-bit systems (default in MiniOS)
linux-image-6.12.38+deb13-rt-amd64 - Real-time kernel for time-critical applications
linux-image-6.12.38+deb13-cloud-amd64 - Optimized for cloud and virtualized environments

📝 Note: Version numbers (like 6.12.38+deb13) change with updates. To find current available kernels:
bash
apt search linux-image-.*-amd64
apt search linux-image-.*-rt-amd64
apt search linux-image-.*-cloud-amd64

🎯 Specialized Use Cases

Real-time computing - RT kernels for audio production, industrial control
Gaming and low-latency - Custom kernels with gaming optimizations
Security hardening - Kernels with additional security patches (grsecurity, etc.)
Hardware compatibility - Newer kernels for recent hardware support
Performance tuning - Custom-compiled kernels with specific optimizations

🛠️ Custom Kernel Features

Custom patches - Apply specific patches for your hardware or use case
Kernel modules - Add support for specialized hardware or filesystems
Compiler optimizations - Build with different optimization flags
Size optimization - Remove unnecessary drivers to reduce kernel size

📈 Common Scenarios

Audio production workstations - Use RT kernel for minimal audio latency
Gaming systems - Apply gaming-specific patches and optimizations
Server environments - Use cloud-optimized kernels for better virtualization
Legacy hardware - Use older kernels for compatibility with vintage systems
Development systems - Test applications against different kernel versions

⚙️ MiniOS Kernel Manager Overview

MiniOS provides two tools for kernel management:

🖥️ MiniOS Kernel Manager (GUI): A user-friendly graphical application for packaging, installing, and managing kernels
⌨️ minios-kernel (CLI): A command-line tool for advanced users and automation

Both tools automatically handle:

Kernel packaging into SquashFS format
Initramfs generation with proper drivers and boot scripts
Installation to the MiniOS kernel repository
Bootloader configuration updates
Kernel activation and switching

⚠️ Important Considerations:

🔑 Administrative Privileges: Both tools require administrative privileges and will prompt for authentication via PolicyKit
🔗 Kernel Compatibility: Ensure kernels are compatible with MiniOS. Repository kernels are recommended
💾 MiniOS Directory: Tools automatically detect the MiniOS directory (/minios/) and verify write permissions
🔄 Automatic Updates: Bootloader configurations are updated automatically when kernels are activated

🖥️ Method 1: Using MiniOS Kernel Manager (GUI)

The graphical kernel manager provides an intuitive interface for all kernel operations.

📝 Steps:

1. 🚀 Launch the Application

bash

minios-kernel-manager

Or search for "MiniOS Kernel Manager" in your application menu.

2. 📦 Package a New Kernel

Using the Package Kernel Tab:

Select Kernel Source:
- Manual Package: Browse and select a local .deb kernel package
- Repository: Choose from available kernels in the Debian/Ubuntu repositories
Configure Compression:
- Select SquashFS compression: zstd (recommended), lz4, lzo, xz, or gzip
Package the Kernel:
- Click "Package Kernel" button
- Monitor progress in the packaging log
- Files are automatically installed to the MiniOS repository

3. 🔄 Manage Installed Kernels

Using the Manage Kernels Tab:

View Available Kernels:
- See all packaged kernels with status badges:
  - ACTIVE: Currently configured kernel
  - RUNNING: Currently booted kernel
  - AVAILABLE: Available for activation
Activate a Kernel:
- Right-click on a kernel and select "Activate Kernel"
- Confirm the activation dialog
- Bootloader configuration is updated automatically
Delete a Kernel:
- Right-click on an inactive kernel and select "Delete Kernel"
- Confirm deletion (cannot be undone)

⌨️ Method 2: Using minios-kernel (CLI)

The command-line tool provides scriptable kernel management capabilities.

⚠️ Administrative Privileges Required:

The CLI tool requires root privileges and will automatically check for them. Run commands with sudo or through pkexec:

bash

sudo minios-kernel list
# or
pkexec minios-kernel activate 6.12.38+deb13-amd64

📝 Basic Commands:

1. 📋 List Available Kernels

bash

sudo minios-kernel list

Shows all packaged kernels with their status.

2. 📦 Package a Kernel

From Repository:

bash

sudo minios-kernel package --repo linux-image-6.12.38+deb13-amd64 -o /tmp/kernel-output

From Local .deb File:

bash

sudo minios-kernel package --deb /path/to/kernel.deb -o /tmp/kernel-output

With Custom Compression:

bash

sudo minios-kernel package --repo linux-image-6.12.38+deb13-rt-amd64 --sqfs-comp lz4 -o /tmp/kernel-output

3. 🔄 Activate a Kernel

bash

sudo minios-kernel activate 6.12.38+deb13-amd64

4. 🗑️ Delete a Kernel

bash

sudo minios-kernel delete 6.12.38+deb13-amd64

5. 📊 Check Status

bash

sudo minios-kernel status

Shows MiniOS directory status and current kernel information.

6. ℹ️ Show Kernel Information

bash

sudo minios-kernel info                           # Information about current active kernel
sudo minios-kernel info 6.12.38+deb13-amd64     # Information about specific kernel

Shows detailed information about a specific kernel including its status and availability.

🔧 Advanced CLI Options:

JSON Output (for scripting):

bash

sudo minios-kernel --json list
sudo minios-kernel --json status
sudo minios-kernel --json info
sudo minios-kernel --json package --repo linux-image-6.12.38+deb13-amd64 -o /tmp/output
sudo minios-kernel --json activate 6.12.38+deb13-amd64
sudo minios-kernel --json delete 6.12.38+deb13-amd64

Advanced Package Options:

bash

# Use custom temporary directory (requires at least 1024MB free space)
sudo minios-kernel package --repo linux-image-6.12.38+deb13-rt-amd64 -o /tmp/output --temp-dir /custom/temp

# Force package lists update if outdated
sudo minios-kernel package --repo linux-image-6.12.38+deb13-rt-amd64 -o /tmp/output --force-update

Help and Usage:

bash

minios-kernel --help                    # General help (doesn't require root)
sudo minios-kernel package --help       # Package command help
sudo minios-kernel list --help          # List command help
sudo minios-kernel activate --help      # Activate command help
sudo minios-kernel info --help          # Info command help
sudo minios-kernel status --help        # Status command help
sudo minios-kernel delete --help        # Delete command help

🔧 Troubleshooting

Common Issues and Solutions:

🚫 MiniOS Directory Not Found

Cause: Tools cannot locate the MiniOS directory
Solution: Ensure you're running from a MiniOS system or the USB drive is properly mounted
Check: Run sudo minios-kernel status to verify directory detection

🔒 Permission Denied

Cause: MiniOS directory is read-only or insufficient permissions
Solution: Ensure you have administrative privileges and the filesystem is writable
Check: Verify the MiniOS directory status in the GUI or CLI

📦 Package Installation Failed

Cause: Corrupted package, network issues, or dependency problems
Solution:
- Verify the package file integrity
- Check network connectivity for repository packages
- Update package lists: sudo apt update

💥 Kernel Panic After Activation

Cause: Incompatible kernel or missing drivers
Solution:
- Boot from rescue mode or older kernel
- Use sudo minios-kernel activate <working-version> to activate a known working kernel
- Check kernel compatibility with your hardware

🔄 System Boots Old Kernel

Cause: Bootloader configuration not updated properly
Solution:
- Re-run kernel activation: sudo minios-kernel activate <version>
- Check that the kernel was properly packaged and installed

⚠️ Hardware Not Working After Kernel Change

Cause: Missing drivers in the new kernel
Solution:
- Verify the SquashFS kernel module file was installed
- Check if the new kernel supports your hardware
- Consider using a different kernel variant

🚨 Kernel Recovery from Original MiniOS Image

If you need to recover from a corrupted or incompatible kernel, you can boot from the original MiniOS ISO/USB:

bash

# Boot from original MiniOS image with from= parameter
# At boot prompt, specify your installed MiniOS device
from=/dev/sda1  # Replace with your actual MiniOS device

Recovery Process: When you boot from the original MiniOS ISO/USB image and specify in the from= parameter the device where MiniOS is installed, the init system detects this and allows you to access your installed MiniOS system. The recovery method depends on whether the original kernel files are still present:

If the original kernel still exists:
- Boot happens seamlessly with the original kernel from the ISO/USB
- Manually activate the original kernel: sudo minios-kernel activate <original-kernel-version>
If the original kernel was deleted:
- Manually copy kernel files from the original MiniOS image and restore them to the appropriate locations on your MiniOS installation
- Manually activate the restored kernel: sudo minios-kernel activate <original-kernel-version>

In both cases, kernel activation requires manual intervention after the recovery process.

🔍 Diagnostic Commands:

Check Current System Status:

bash

sudo minios-kernel status
sudo minios-kernel info     # Current active kernel info
uname -r                    # Current running kernel
cat /proc/version           # Kernel version details
lsmod                       # Loaded kernel modules

Verify Kernel Files:

bash

ls -la /minios/kernels/     # List packaged kernels
ls -la /minios/boot/        # List boot files

Check Bootloader Configuration:

bash

grep -r "vmlinuz" /minios/boot/  # Find kernel references in boot configs

📋 File Structure Overview

The MiniOS Kernel Manager automatically manages these files:

Kernel Repository Structure:

/minios/
├── 01-kernel.sb                   # Active kernel module (standard location)
├── kernels/                       # Repository of inactive/alternative kernels
│   ├── 01-kernel-<version>.sb     # SquashFS kernel modules
│   ├── vmlinuz-<version>          # Kernel binaries
│   └── initrfs-<version>.img      # Initial RAM filesystems
├── boot/
│   ├── vmlinuz-<version>          # Active kernel binary
│   ├── initrfs-<version>.img      # Active initial RAM filesystem
│   ├── syslinux/
│   │   └── syslinux.cfg           # SYSLINUX bootloader config
│   └── grub/
│       └── grub.cfg               # GRUB bootloader config

Note: The standard 01-kernel.sb module that comes with MiniOS contains additional drivers beyond those included in the original repository kernel packages. These additional drivers provide enhanced hardware compatibility for wireless adapters and storage devices.

Status Indicators:

ACTIVE: Kernel configured in bootloader (will boot on next restart)
RUNNING: Currently executing kernel
AVAILABLE: Packaged and ready for activation

Automatic Operations:

✅ Kernel packaging and compression
✅ Initramfs generation with proper drivers
✅ Installation to MiniOS repository
✅ Bootloader configuration updates
✅ Symlink management for active kernels
✅ Cleanup of temporary files

🎯 Best Practices

Kernel Selection:

Use kernels from official Debian/Ubuntu repositories when possible
Test new kernels in non-production environments first
Keep at least one known working kernel for recovery

Before Installing:

Verify MiniOS directory is writable
Ensure sufficient disk space (kernels can be 100-500MB)
Update package lists for repository kernels

After Installation:

Test the new kernel thoroughly
Verify all hardware functions correctly
Keep previous kernel as backup until new one is proven stable

Recovery Planning:

Always maintain a working kernel backup
Know how to boot from rescue media if needed
Document which kernels work with your hardware configuration

Kernel Management in MiniOS 🔧 ​

🤔 Why Replace the Kernel? ​

🔧 Different Debian Kernel Flavours ​

🎯 Specialized Use Cases ​

🛠️ Custom Kernel Features ​

📈 Common Scenarios ​

⚙️ MiniOS Kernel Manager Overview ​

⚠️ Important Considerations: ​

🖥️ Method 1: Using MiniOS Kernel Manager (GUI) ​

📝 Steps: ​

1. 🚀 Launch the Application ​

2. 📦 Package a New Kernel ​

3. 🔄 Manage Installed Kernels ​

⌨️ Method 2: Using minios-kernel (CLI) ​

⚠️ Administrative Privileges Required: ​

📝 Basic Commands: ​

1. 📋 List Available Kernels ​

2. 📦 Package a Kernel ​

3. 🔄 Activate a Kernel ​

4. 🗑️ Delete a Kernel ​

5. 📊 Check Status ​

6. ℹ️ Show Kernel Information ​

🔧 Advanced CLI Options: ​

JSON Output (for scripting): ​

Advanced Package Options: ​

Help and Usage: ​

🔧 Troubleshooting ​

Common Issues and Solutions: ​

🚫 MiniOS Directory Not Found ​

🔒 Permission Denied ​

📦 Package Installation Failed ​

💥 Kernel Panic After Activation ​

🔄 System Boots Old Kernel ​

⚠️ Hardware Not Working After Kernel Change ​

🚨 Kernel Recovery from Original MiniOS Image ​

🔍 Diagnostic Commands: ​

📋 File Structure Overview ​

Kernel Repository Structure: ​

Status Indicators: ​

Automatic Operations: ​

🎯 Best Practices ​

Kernel Selection: ​

Before Installing: ​

After Installation: ​

Recovery Planning: ​

Kernel Management in MiniOS 🔧

🤔 Why Replace the Kernel?

🔧 Different Debian Kernel Flavours

🎯 Specialized Use Cases

🛠️ Custom Kernel Features

📈 Common Scenarios

⚙️ MiniOS Kernel Manager Overview

⚠️ Important Considerations:

🖥️ Method 1: Using MiniOS Kernel Manager (GUI)

📝 Steps:

1. 🚀 Launch the Application

2. 📦 Package a New Kernel

3. 🔄 Manage Installed Kernels

⌨️ Method 2: Using minios-kernel (CLI)

⚠️ Administrative Privileges Required:

📝 Basic Commands:

1. 📋 List Available Kernels

2. 📦 Package a Kernel

3. 🔄 Activate a Kernel

4. 🗑️ Delete a Kernel

5. 📊 Check Status

6. ℹ️ Show Kernel Information

🔧 Advanced CLI Options:

JSON Output (for scripting):

Advanced Package Options:

Help and Usage:

🔧 Troubleshooting

Common Issues and Solutions:

🚫 MiniOS Directory Not Found

🔒 Permission Denied

📦 Package Installation Failed

💥 Kernel Panic After Activation

🔄 System Boots Old Kernel

⚠️ Hardware Not Working After Kernel Change

🚨 Kernel Recovery from Original MiniOS Image

🔍 Diagnostic Commands:

📋 File Structure Overview

Kernel Repository Structure:

Status Indicators:

Automatic Operations:

🎯 Best Practices

Kernel Selection:

Before Installing:

After Installation:

Recovery Planning: