Bootti/grub häviää windowssiin mennessä

Antamaasi viestiketjua seuraten löysin tämän (kopsaan vain näkyviin joitain kohtia koska minulla ei ole omaa kokemusta asiasta. Tästä aiheesta näyttää olevan useita erilaisia ratkaisuja ja valmistaja kohtaisia ohjeita. Ei ihan joka-pojan-ja-tytön jobi! Tärkein esi-valmistelu on: Tee varmuuskopio windows levystä tai ainakin EFI-partitiosta ennen kuin alat kokeilemaan.):

Caution:
New installs must use only current versions of Installer as old ones had major bug that erased all partitions even if it says it only over writes Ubuntu partition. Newest 16.04

For more info on UEFI boot install & repair - Regularly Updated :
http://ubuntuforums.org/showthread.php?t=2147295

Systems that only boot Windows from UEFI.
Per UEFI standard you should be able to boot any entry in UEFI boot menu. But some vendors have modified UEFI code to only boot the Windows efi file. The UEFI looks for the Windows file name and only boots it. (Note for Acer, it requires "trust" settings in UEFI)
Installing Grub for UEFI secure boot is only possible if you have booted your system using EFI with the 64bit version with secure boot on. A few systems will only boot with UEFI and secure boot on or with CSM (BIOS) if secure boot is off. Best to test system to see which modes it boots in. In secure boot mode it will only show/allow systems that have secure boot. You may have to change UEFI settings or set password to allow other devices to boot.

Backup entire efi partition before making changes.

A: Manually rename files efi hard drive boot files in efi partition /EFI/Boot

In Boot-Repair "Use the standard EFI file" Should do the same as these manual instrutions by copying shimx64.efi to /EFI/Boot/bootx64.efi for fallback or hard drive boot from UEFI menu.

Rename /efi/boot/bootx64.efi, copy shim or grub into /efi/boot and name it bootx64.efi Then boot harddrive entry in UEFI menu.
Older rename of Windows efi file not recommended anymore. (old versions of Boot-Repair did rename the Windows efi file)

From live installer booted in UEFI mode, mount the efi partition on hard drive, lines with # are comments only: Mount ESP - efi system partition. check which partition is FAT32 with boot flag. Often sda1 or sda2 but varies.
# if your ESP is not sda1 change this to correct partition
sudo mount /dev/sda1 /mnt
only if /EFI/Boot not already existing, run the mkdir command,
sudo mkdir /mnt/EFI/Boot
sudo cp /mnt/EFI/ubuntu/* /mnt/EFI/Boot
# If new folder created, the bootx64.efi will not exist, skip backup command
sudo mv /mnt/EFI/Boot/bootx64.efi /mnt/EFI/Boot/bootx64.efi.backup
# make grub be hard drive boot entry in UEFI. Then boot hard drive entry in UEFI menu.
sudo mv /mnt/EFI/Boot/grubx64.efi /mnt/EFI/Boot/bootx64.efi
# You may need new hard drive entry (uses default of sda1 for ESP):
sudo efibootmgr -c -L "UEFI Hard drive" -l "\EFI\Boot\bootx64.efi"
# confirm entries:
sudo efibootmgr -v