Surface Pro 3 Grub Boot

How to install grub2 in efi after it failed to install it automatically

Mount the installed ubuntu partition on /mnt

mount /dev/sdaX /mnt
for i in /dev /dev/pts /proc /sys; do mount --bind $i /mnt$i; done

Mount the efi partition in the ubuntu system partition

mount /dev/sdaX /mnt/boot/efi

Chroot into mnt chroot /mnt
Check if you got access to the efi boot manager entries
```
efibootmgr -v
```
If you get errors like Input/Output error for Boot0003 or so you have to enter the entries manually later.
install grub:
```
apt-get update && apt-get install --reinstall grub-efi
grub-install 
update-grub
```
If you got no error you should be done.
If you got an error on efibootmgr before you are NOT done.
Open another terminal with sudo access
Look up all boot entries with
```
efibootmgr -v
```
delete all unused entries with
```
efibootmgr -b <X> -B
```
- -b X defines the Boot000X number
- -B removes
Àdd the boot entry for your system
```
efibootmgr -c -d /dev/sda -p X -L "BootEntryName" -l "\efi\ubuntu\grubx64.efi"
```
- -c creates new entry -d is the disk -p is the sdaX entry of the EFI partition
- -L is the shown Name on the Grub Loader -l is the path on the EFI Partition to the loader
on ubuntu it SHOULD BE \efi\ubuntu\grubx64.efi but verify first!
YES BACKSLASHES NEEDED