# 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:
   ```bash
   chmod +x grub-repair.sh
   ```
3. Run with sudo:
   ```bash
   sudo ./grub-repair.sh [OPTIONS] COMMAND
   ```

## Usage

### Basic Commands

```bash
# 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

```bash
# 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

```bash
# 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

```bash
# 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:
   ```bash
   sudo ./grub-repair.sh detect
   ```
3. **Complete Repair**: Perform the repair in one command:
   ```bash
   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:
```bash
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
```bash
# 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
```bash
# Complete repair with backup
sudo ./grub-repair.sh -d /dev/sda -p 1 -b fix-boot
```

### Scenario 3: Multiple System Recovery
```bash
# 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.