GRUB and EFI Repair Script

A comprehensive command-line tool designed to repair GRUB bootloader and EFI boot entries from a live ISO environment. This script is specifically crafted for system administrators and users who need to recover a system that won't boot due to corrupted or missing boot configuration.

Features

• Live ISO Detection: Automatically detects if running from a live ISO environment
• System Detection: Identifies available disks, partitions, and bootable systems
• Safe Mounting: Properly mounts target systems with all necessary bind mounts
• GRUB Installation: Installs/reinstalls GRUB bootloader with proper EFI support
• Configuration Updates: Updates GRUB configuration to detect all installed kernels
• EFI Repair: Repairs EFI partition and boot entries
• Backup Creation: Creates backups before making changes
• Comprehensive Logging: Logs all operations for troubleshooting
• Safe Cleanup: Properly unmounts and cleans up after operations

Prerequisites

• Root Access: Script must be run as root (use sudo)
• Live ISO Environment: Designed to run from a live Linux ISO
• Target System: An installed Linux system with GRUB bootloader
• Basic Knowledge: Understanding of disk partitions and Linux boot process

Installation

1. Download the script to your live ISO environment
2. Make it executable:

   chmod +x grub-repair.sh
   

3. Run with sudo:

   sudo ./grub-repair.sh [OPTIONS] COMMAND
   

Usage

Basic Commands

# Show help
sudo ./grub-repair.sh --help

# Detect available systems
sudo ./grub-repair.sh detect

# Show current status
sudo ./grub-repair.sh status

# Clean up and unmount
sudo ./grub-repair.sh clean

System Operations

# Mount a system (e.g., /dev/sda1)
sudo ./grub-repair.sh -d /dev/sda -p 1 mount

# Unmount current system
sudo ./grub-repair.sh unmount

# Create backup of current configuration
sudo ./grub-repair.sh backup

GRUB Operations

# Install/reinstall GRUB
sudo ./grub-repair.sh install-grub

# Update GRUB configuration
sudo ./grub-repair.sh update-grub

# Check and repair EFI partition
sudo ./grub-repair.sh -d /dev/sda check-efi

Complete Repair

# Complete boot repair with backup
sudo ./grub-repair.sh -d /dev/sda -p 1 -b fix-boot

# Complete repair without backup
sudo ./grub-repair.sh -d /dev/sda -p 1 fix-boot

Command Line Options

Option	Long Option	Description
-h	--help	Show help message
-v	--verbose	Enable verbose output
-d	--device	Specify target device (e.g., /dev/sda)
-p	--partition	Specify partition number (default: 1)
-m	--mount	Specify mount point (default: /mnt)
-b	--backup	Create backup before operations
-f	--force	Force operations without confirmation
-l	--log	Specify log file path

Commands Reference

detect

Scans and displays all available disks, partitions, and bootable systems.

mount

Mounts the target system with proper bind mounts for chroot operations.

unmount

Safely unmounts all mounted filesystems in the correct order.

backup

Creates a timestamped backup of current GRUB configuration and EFI contents.

install-grub

Installs or reinstalls GRUB bootloader to the target system.

update-grub

Updates GRUB configuration to detect all installed kernels and OS entries.

check-efi

Checks and repairs EFI partition and boot entries.

fix-boot

Performs a complete boot repair sequence (mount + install + update + repair).

status

Shows current status of mounted systems and available configurations.

clean

Cleans up temporary files and unmounts all systems.

Typical Workflow

1. Boot from Live ISO: Start your system from a live Linux ISO
2. Detect Systems: Identify your target system:

   sudo ./grub-repair.sh detect
   

3. Complete Repair: Perform the repair in one command:

   sudo ./grub-repair.sh -d /dev/sda -p 1 -b fix-boot
   

4. Reboot: Restart your system and test the boot

Troubleshooting

Common Issues

• Permission Denied: Ensure you're running as root with sudo
• Device Not Found: Verify device names with lsblk or fdisk -l
• Mount Failures: Check if partitions are already mounted elsewhere
• GRUB Installation Fails: Verify EFI partition is properly mounted

Verbose Mode

Enable detailed output for troubleshooting:

sudo ./grub-repair.sh -v -d /dev/sda -p 1 fix-boot

Log Files

The script creates detailed logs in /tmp/grub-repair-YYYYMMDD-HHMMSS.log

Safety Features

• Automatic Backups: Creates backups before making changes
• Safe Mounting: Uses proper bind mounts and handles dependencies
• Cleanup Traps: Automatically cleans up on script exit
• Error Handling: Comprehensive error checking and reporting
• Live ISO Detection: Warns if not running from live environment

Examples

Scenario 1: Simple GRUB Reinstall

# Mount system
sudo ./grub-repair.sh -d /dev/sda -p 1 mount

# Install GRUB
sudo ./grub-repair.sh install-grub

# Update configuration
sudo ./grub-repair.sh update-grub

# Unmount
sudo ./grub-repair.sh unmount

Scenario 2: Complete EFI Repair

# Complete repair with backup
sudo ./grub-repair.sh -d /dev/sda -p 1 -b fix-boot

Scenario 3: Multiple System Recovery

# Check available systems
sudo ./grub-repair.sh detect

# Repair first system
sudo ./grub-repair.sh -d /dev/sda -p 1 fix-boot

# Clean up
sudo ./grub-repair.sh clean

# Repair second system
sudo ./grub-repair.sh -d /dev/sdb -p 1 fix-boot

Contributing

This script is designed to be robust and user-friendly. If you encounter issues or have suggestions for improvements, please:

1. Test thoroughly in your environment
2. Document the issue or enhancement
3. Provide detailed error messages and system information

License

This script is provided as-is for educational and recovery purposes. Use at your own risk and always test in a safe environment first.

Disclaimer

This tool modifies critical boot configuration files. Always create backups and test in a safe environment before using on production systems. The authors are not responsible for data loss or system damage resulting from the use of this script.