dual boot 14.04 / 17.04 lost grub menu

I had ubuntu14.04LTS running and installed ubuntu 17.04 making a partition. So I got 2 choices at startup. This worked fine until a couple of weeks. I assume after a 14.04 update, the initial menu (grub?) disapeared, and notebook starts directly on 14.04.

I tryed boot-repair with this result: GPT detected. Please create a BIOS-Boot partition (>1MB, unformatted filesystem, bios_grub flag). This can be performed via tools such as Gparted. Then try again. Alternatively, you can retry after activating the [Separate /boot/efi partition:] option.

Things from there are too complicated in forums, I am not an expert, just a user.

Partitions are still there with all the content.

bootinfo from boot-repair: http://paste.ubuntu.com/25575784/

Hope someone can help. Thanks.

Your grub.cfg should be this:

cat /boot/efi/EFI/ubuntu/grub.cfg
search.fs_uuid 94ce33db-7654-4e3e-a9be-a3063bb155cf root hd0,gpt4 
set prefix=($root)'/boot/grub'
configfile $prefix/grub.cfg

You get UUID from this(I got it from the Boot-Repair report).

sudo blkid -c /dev/null -o list

And you want to change first line to UUID of sda4 & gpt4 to gpt6, copy & paste UUID from above command. Orcopy this line & paste. Best to also add # to existing line as first char changing to a comment. Then easier to revert if required.

search.fs_uuid 00aee336-b9ae-4c75-8edc-a19adb0b5451  root hd0,gpt6

sudo nano /boot/efi/EFI/ubuntu/grub.cfg

It should end up like this:

search.fs_uuid 00aee336-b9ae-4c75-8edc-a19adb0b5451  root hd0,gpt6
#search.fs_uuid 94ce33db-7654-4e3e-a9be-a3063bb155cf root hd0,gpt4 
set prefix=($root)'/boot/grub'
configfile $prefix/grub.cfg