Ntboot7z
If you dual-boot Linux and Windows, your GRUB bootloader is already in place. Adding NTBoot7z as a menu entry takes 30 seconds. You no longer need to rely on Windows’ buggy boot manager.
Potential malware / suspicious file – Uncommon or incorrectly typed names like ntboot7z.exe may appear in questionable downloads, forum posts, or malicious payloads. If you found a file with that name, scan it with updated antivirus software before running. ntboot7z
Imagine you have win10_22h2.iso and win11_23h2.iso. Instead of creating two partitions or two USB drives, you just store both files. Your boot menu lists both, thanks to NTBoot7z’s ability to chainload each independently. If you dual-boot Linux and Windows, your GRUB
| Problem | Likely Cause | Solution |
| :--- | :--- | :--- |
| Error: file not found | NTBoot7z cannot locate the ISO | Use absolute paths like (hd0,1)/isos/win10.iso |
| Invalid or unsupported executable format | Mixing 32-bit and 64-bit | Ensure NTBoot7z matches your firmware (x64 UEFI needs x64 binary) |
| 0xc000000f (Boot selection failed) | BCD inside ISO is corrupted or missing | Extract the ISO’s \boot\BCD and replace with a known good one (using bcdedit) |
| Secure Boot violation | Microsoft doesn’t sign NTBoot7z | Temporarily disable Secure Boot or sign NTBoot7z with your own MOK |
| Slow boot from USB 2.0 | On-the-fly extraction is slow | Copy ISO to RAM first: ntboot7z --mem iso=/path/to.iso | Potential malware / suspicious file – Uncommon or
Place multiple Windows editions (Home, Pro, LTSC) into one .7z using different folders and use grub4dos scripting to select which one to boot via ntboot7z /boot/win_all.7z /sources/folder.