Ahmed x86 - GRUB Fixer 🛠️

About the Project

GRUB Fixer (V16 - Ultimate Automation, Legacy BIOS, OS Prober, Universal UEFI & In-Situ Repair) is an automated, bulletproof Bash script designed to repair the GRUB bootloader on both UEFI and Legacy BIOS Linux systems. V16 transforms the script into a true "Universal Rescue Weapon," bringing In-Situ (Local) Repair capabilities, Dynamic 32-bit/64-bit UEFI Detection, a dynamic execution timer with gamer-style human responses, intelligent dual-boot detection (OS Prober), and the powerful Zero-Interaction "Pro Mode" that parses /etc/fstab to map and mount complex layouts (like Btrfs subvolumes) in seconds.

✨ New in V16 (The In-Situ Update)

• In-Situ (Local) Mode Detection: The script intelligently detects if it's being run directly from your installed OS (e.g., booted via Super GRUB2 Disk or rEFInd) rather than a Live USB. It safely bypasses the complex chroot environment and repairs GRUB locally in seconds, automatically handling unmounted EFI variables (efivarfs) and boot partitions.

⚙️ Key Additions in V15, V14, V13 & V12

• Dynamic UEFI 32-bit Detection (V15): Acts as a flawless Universal Bootloader Rescue tool by intelligently detecting rare 32-bit UEFI architectures and automatically switching the GRUB target to i386-efi.
• Dynamic Execution Timer (V14): The script now calculates the total execution time and delivers gamer-style, human-like status messages based on how fast the repair was completed (e.g., "Wait, did I just fix that?! You didn't even get to sip your coffee! ☕😂🏃‍♂️").
• OS Prober Integration (V13): Solves the issue where Windows or other Linux distros disappear from the GRUB menu after a repair. V13 automatically modifies /etc/default/grub to enable GRUB_DISABLE_OS_PROBER=false, ensuring all installed operating systems are detected and listed correctly.
• Legacy BIOS (i386-pc) Support (V12): The script automatically detects if your system lacks an EFI partition and dynamically switches to Legacy mode.
• Smart Target Disk Extraction (V12): In Legacy BIOS mode, uses lsblk -no PKNAME to intelligently extract the parent disk from your root partition (e.g., /dev/sda), ensuring flawless GRUB installation on older machines.

🧠 Core Features (From V11 & V10)

• Zero-Interaction FSTAB Parsing (Tier 1): Automatically scans devices to locate and parse your system's /etc/fstab. It resolves UUID and PARTUUID tags instantly, mapping out your exact system layout (Root, Boot, EFI, and Btrfs subvolumes) without manual input.
• 3-Tier Fallback System: If fstab is missing, encrypted, or rejected, the script gracefully falls back to Smart Auto-Detection (Tier 2), and finally to fully Manual Input (Tier 3), guaranteeing a crash-free experience.
• Bulletproof Btrfs Loop: In manual/fallback mode, an interactive loop ensures required subvolumes (e.g., @, @home, @log) are mounted in the correct hierarchy with strict input validation.
• Dynamic EFI Mount Logic: Solves the common "missing kernel" trap by automatically verifying and applying the correct EFI mount path (/boot vs /boot/efi), which is critical for Archinstall and CachyOS setups.
• VM & NVRAM Rescue: Uses the --removable flag to guarantee booting on Virtual Machines (QEMU/KVM) and stubborn UEFI firmware that drop NVRAM variables.

💎 Advanced Rescue Tech

• Blackbox Logging System: Automatically captures and logs all standard output and errors directly to /var/log/grub-fixer.log for a complete forensic troubleshooting trail.
• Pipeline Ready: Fully compatible with curl | bash pipelines thanks to TTY redirection for all user inputs.
• OS Detection: Automatically sources /etc/os-release from the target system to set the correct Bootloader ID.
• Safety & Cleanup: Forced set -e for immediate halt on errors and automatic umount -R cleanup to prevent mount conflicts.

🛠️ Usage

You can choose between the quick one-liner or the manual download method depending on your environment.

Option 1: Quick One-Liner (Recommended)

Run the script directly from your terminal in any Live Linux environment (or booted broken OS) without downloading. (Note: sudo is required):

curl -sL https://raw.githubusercontent.com/ahmed-x86/grub-fixer/main/grub-fixer.sh | sudo bash

Option 2: Manual Download & Execute

If you prefer to have the file locally or want to audit the code before running:

curl -O https://raw.githubusercontent.com/ahmed-x86/grub-fixer/main/grub-fixer.sh
chmod +x grub-fixer.sh
sudo ./grub-fixer.sh

📜 Version History

📋 System Requirements

• Environment: Live Linux ISO/USB (Arch, CachyOS, Fedora, Ubuntu, etc.) OR directly from your installed OS if booted via a rescue tool.
• Architecture: Target system must be UEFI (x86_64-efi or i386-efi) OR Legacy BIOS (i386-pc).
• Privileges: Sudo/Root access required.

⚠️ Disclaimer

While highly automated, GRUB repair touches critical system files. Always verify the auto-detected partitions, fstab layout, and subvolumes before confirming the repair process, especially on dual-boot systems.