When Linux Won’t Boot: Professional Recovery with Super Grub2 Disk and Rescatux
There are two kinds of Linux users: those who have already broken their boot… and those who still haven’t resized a partition late on a Sunday night.
When a machine stops booting, the difference between solving it in 15 minutes or losing an entire afternoon is having a plan: regain access first, then repair methodically. For that, this kit is extremely effective:
- Super Grub2 Disk (SG2D): to boot systems when the bootloader is broken.
- Rescatux (with Rescapp): to repair using guided assistants: GRUB, menus, UEFI, users, etc.
The goal of this article is to help you act like “production-grade” support: fast, safe, and with traceability.
1) What “won’t boot” means (and why it happens)
Booting isn’t magic: it’s a chain. If one link breaks, you’re locked out.
When you resize partitions, install another OS, or switch boot modes, the most common failure point is link 2 or 3.
2) Quick symptom-based diagnosis
| Symptom | Likely cause | Recommended solution |
|---|---|---|
| Black screen / “No bootable device” | Boot order changed, lost UEFI entry, wrong disk set first | Rescatux (to edit UEFI/entries) or SG2D (to get in “no matter what”) |
| “grub rescue>”, “no such partition”, “unknown filesystem” | Partition moved/resized, UUID changed, GRUB points to something that no longer exists | Use SG2D to boot the OS, then repair GRUB from inside |
| Broken dual boot after installing Windows | Windows rewrote the bootloader or prioritized its own entry | Boot Linux with SG2D, then use Rescatux/Rescapp for guided repair |
| After cloning a disk or swapping an SSD | UEFI entries still point to the old disk, UUID/paths changed | Rescatux to review/create UEFI entries, then reinstall the bootloader |
3) The golden rule: get in first, fix later
In emergencies, the correct order is almost always:
- Boot somehow (SG2D or Rescatux)
- Back up what matters (at least /home, SSH keys, projects)
- Repair the boot calmly
- Validate by rebooting without the USB
This avoids the classic: “I tried to fix GRUB and now I can’t even copy my files.”
Super Grub2 Disk (SG2D)
What it is: SG2D is a bootable environment focused on letting you start operating systems even if they won’t boot the usual way. In plain terms: it’s the bridge back into Linux/Windows when the boot process breaks.
4) When to choose SG2D
Use it when:
- Your priority is getting into the system right now
- You know or suspect the problem is GRUB/bootloader
- There were recent changes: partitions, dual boot, updates, cloning, disk replacement
5) Recommended workflow with SG2D
Note: SG2D isn’t “the final fix”: it’s the emergency entry point. If you want guided assistants, extra tools, or deeper UEFI work, Rescatux is usually more convenient.
Rescatux (and its assistant Rescapp)
What it is: Rescatux is a rescue-focused live distro that includes Rescapp, an assistant with guided options to solve common issues (boot, GRUB, UEFI, etc.). The idea is: “less terminal, clearer steps.”
6) When to choose Rescatux
Use it when:
- You want a more “assisted” repair flow
- You need extra tools beyond just booting
- You suspect UEFI issues (entries, order, EFI partition)
- You want to solve common cases with a wizard and move on
7) Recommended flow with Rescatux
Important ethical note: Rescatux can also provide account/password-related options in some scenarios. Use it only to recover systems you own or where you have explicit permission from the owner.
8) Emergency checklist (copy/paste)
Before running “things that write to disk”, confirm:
- Am I in UEFI or Legacy mode?
- Which disk is the real system disk? (don’t guess)
- Is there encryption (LUKS/BitLocker)? If yes, the approach changes.
- Do I have a backup of critical data?
- Am I repairing the correct boot target (right disk/partition)?
After you get in: permanent repair (without marrying a distro)
Once you’ve managed to boot (with SG2D) or Rescatux has left the system consistent, the permanent fix usually looks like:
Safe (non-destructive) diagnostic commands
# Check UEFI mode (if /sys/firmware/efi exists, it’s UEFI)
ls /sys/firmware/efi 2>/dev/null && echo "System is in UEFI mode" || echo "System is in Legacy mode"
# List disks and partitions with filesystem information
lsblk -f
# Show UUIDs for all partitions
blkid
# Show mounted partitions
mount | grep "^/dev"
# Show UEFI entries (only in UEFI mode)
efibootmgr -vConceptual repair by boot type
| Type | Installed where | How to repair (conceptual) |
|---|---|---|
| BIOS/Legacy | MBR/boot sector + configuration files in /boot | Reinstall GRUB to the disk (e.g., grub-install /dev/sda) and regenerate config (update-grub) |
| UEFI | EFI partition (FAT32) with .efi files + an NVRAM entry | Install GRUB to the EFI partition (e.g., grub-install --target=x86_64-efi --efi-directory=/boot/efi) and regenerate config |
Professional note: The exact implementation varies by distro, so the most professional approach is: “check your distro documentation and use SG2D/Rescatux as an access path, not a replacement for the official method.”
9) Final recommendation: the USB you don’t use… until it saves the day
Keep a USB with one of these tools (or both). You won’t use it often, but when boot fails outside business hours, that flash drive will feel like magic.
SG2D: to get in when everything else fails
Rescatux: to fix with guided tools when you want help
Updated:
And that’s it: your contingency plan is now better than half the offices on the planet.