To fix Windows 10 broke UEFI bootloader

Some computers can be a tricky, if using the dual boot. HP Pro 6300 MT seems to be one of the if using the UEFI-mode. With Legacy-mode, there is no problem, but Windows cannot boot if it is installed on the UEFI-mode.

I do not know if it is a new feature in Windows 10, but it breaks boot every now and then. The solution is quite simple.

1. Boot to the computer using Super Grub 2 UEFI boot USB or CD

SG2uefi.img image can be installed to an USB using Etcher for example.

2. Mount EFI-partition and copy and rename EFI/Microsoft folder as an administrator

– to find and mount the EFI-partition run commands
sudo blkid
sudo mount /dev/sdXY /mnt ## where X=drive and Y=partition
An example sudo mount /dev/sda2 /mnt

3. Copy and rename the copied Microsoft folder like Microsoft.orig

4. Copy grubx64.efi file from EFI/ubuntu folder to the EFI/Microsoft folder and rename grubx64.efi as bootmgfw.efi

5. After that edit /boot/grub/grub.cfg file for setting the right path for booting Windows also like

chainloader /EFI/Microsoft.orig/Boot/bootmgfw.efi

the right path

This solution is not perfect, because Windows entry disappears when updating grub bootloader, so the better solution is to make a custom entry for Windows -> Custom entry

menuentry ’Windows 10′ {
insmod part_gpt
insmod fat
set root=’hd0,gpt2’

chainloader /EFI/Microsoft.orig/Boot/bootmgfw.efi