Rescatux was the standard for grub repair in MBR and EFI systems. It has a ton of tools. Recent updates arent compatible with new machines and the system wont load anymore. If you have a GPU+CPU machine (like a AMD A6 R4) forget to use rescatux.
However if your machine is compatible, use rescatux as it's probably the best tool for repairing boot problems, disk management and thousand of thing more.
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