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learningtoc0d3 avatar Ubuntu

How to reinstall grub to replace Windows bootloader

ar flag
learningtoc0d3

I currently have a dual boot of Ubuntu and Windows which I did by following this video. The video tells to make an extended partition on your hard drive which will contain the Ubuntu partition and the swap partition. However, it also tells you to install the grub bootloader to the Ubuntu partition so that in case you don't like Ubuntu and want to revert back, you can just remove the partition. Otherwise, you'd have your Windows bootloader overwritten and have to use grub to boot into Windows which may be undesirable to some. To actually boot into grub in the Ubuntu partition, he uses EasyBCD on Windows.

So now, I essentially am faced with two boot loader screens. EasyBCD and grub and then I can finally boot Ubuntu. I tried to use gparted to set the boot flag on the Ubuntu partition in the extended partition but for some reason, that fails to work. It just shows a black screen with an underline blinking.

How can I make it so that I immediately boot into grub? I now know that I can recreate the Windows bootloader after deleting it so I am not worried about overwriting it and moreover, I do not use Windows much anyway so I'd likely never have to reinstall the Windows bootloader on my machine again. I have researched a bit into this and haven't found anyone in quite the same predicament as me so I decided to ask myself. I can't risk losing any of my files on Windows and thus don't want to follow answers to questions that aren't exactly like mine.

I believe my PC uses legacy boot and not UEFI since I am limited to 4 partitions on my hard drive. This is how my partitions look like. I removed the swap partition for unrelated reasons.

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Nmath avatar
ng flag
Nmath
The advice you followed was bad and inaccurate. If I were you, I would format (erase) the disk using the GPT partition scheme and reinstall the operating system(s) you intend to use using UEFI. The limitation of 4 partitions is not conducive to dual boot. GPT can have up to 128 partitions. If you cannot afford to lose data, you need to have better backups. Data loss can happen at any time and without apparent reason. Manipulating partitions and bootloaders and installed operating systems without backups is playing with fate.
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oldfred avatar
cn flag
oldfred
With old BIOS/MBR, you only have one MBR to boot from. EasyBCD is a Windows work around, but grub2 highly suggests not to install to PBR or partition. But if you use EasyBCD you have to install grub to PBR. If you have both Windows repair/recovery flash drive to restore Windows boot loader & Ubuntu live installer to install grub, you can just install grub to MBR. Grub will only boot working Windows, so sometimes you may need to reinstall Windows boot loader to MBR. If any files are important, you must have good backups as any incorrect changes or hardware failure & you lose your data.
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Nmath avatar
ng flag
Nmath
You do not need EasyBCD. GRUB boots Ubuntu and hands off to the Windows bootloader when Windows is chosen. GPT/UEFI uses a single EFI partition to boot all operating systems.
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