Recover Dual boot Windows - Kubuntu

[oshunluvr]

IME, If you have an EFI partition somewhere, the installer "finds" it and attempts an GRUB-EFI install. If you install to a totally non-EFI system, it doesn't.

As to the GPT vs. MBR partitioning scheme, GRUB (aka GRUB-PC and GRUB2, the GRUB we're using here); GPT partitioning does not provide a space for non-EFI GRUB to install on a disk. So GRUB looks for a small slice for itself. As my how-to on this topic explains, you can use the space from sector 34 to sector 2047 as this area is not used by GPT nor is it used during normal partitioning because the modern partitioning tools start partitions at sector 2048 by default to provide proper partition alignment. If you have an EFI partition, GRUB finds that space and uses it. BTW, you can also wedge the EFI partition in the same unused space.

A GRUB partition is of type EF02 and is left unformatted. An EFI partition is of type EF00 and is formatted FAT32.

[Qqmike]

OK, so now what? As jlittle said, Windows 7 is using a legacy BIOS boot. Thus, it seems we have to stick with that--a legacy BIOS boot. So ... We need to delete that ESP, the EFI System Partition--just delete it--I think it is sdd4. Then, to prepare for a legacy BIOS boot and a non-UEFI installation of Kubuntu, the BIOS Boot Partition must be added to the GPT as per Oshunluvr's how-to. That would set things up to do a straight BIOS boot of the PC and a Legacy installation of Kubuntu. If that fails to boot, then run Boot-Repair to fix that booting (which it would do by re-installing GRUB properly). In particular, ignore everything about doing an EFI booting. The issue here is Windows 7: it appears to NOT use a UEFI boot. Thus, the PC's BIOS must be set up NOT to boot by UEFI.

Does this make sense?

[Qqmike]

Btw, if you do go for the Legacy Boot setup, as discussed above, you won't want that ESP sdd4 to be visible to an installer. Instead of deleting that ESP (partition), you can simply "turn it off" by using GParted or KDE Partition Manager to remove the boot flag on that partition (sdd4). The partition will still be there, with its contents, but will not be seen as an ESP. (If you put the boot flag back on, then it will again be seen as an ESP.)

[slamelov]

Finally solved, but many doubts. Basically, I used boot repair and create boot, with advanced options, in all devices:

http://paste.ubuntu.com/p/9NJvZcqnND/

Now, probably, I have a big mess, but, I least, I can boot in Windows and Kubuntu.

Thanks for all the answers

[Qqmike]

Congratulations, salmelov. I'm not sure I understand it, but that doesn't matter . What counts is that you do and you know how to maintain it in case of updates (to Windows bootloader and/or GRUB updates). Good work.