Adding LibreElec to GRUB2 in Uefi multi-boot system

    Hi guys.


    My system used to have an nvme drive formated in MBR format and had a Windows10 partition and a LibreElec Partition, to create a multiboot menu and set LibreElec as default i just added the LibreElec to the boot menu using EasyBCD and changed it to default and everything worked.


    Recently i decided to convert my system to UEFI/GPT, and things were not so simple.


    Now my nvme drive has Windows10 only (GPT/UEFI).

    I have another smaller 16GB nvme drive with LibreElec only (UEFI too)

    And now i have UBUNTU on a 32GB USB 3.0 drive.


    Since Easy BCD isn't much use in a UEFI system, i decided to try EasyUefi.

    From EasyUefi i am able to set "one-time boot" for LibreElec and Ubuntu, and both systems boot correctly that "one-time" and the second reboot boots windows again.

    From the motherboard UEFI (what we call BIOS these days :)) i can boot all three systems.

    From inside Ubuntu the command "uefibootmgr" shows me the three systems available.


    But what i want is a boot menu, and set it default for LibreElec.


    I was able from the motherboard UEFI to set the UBUNTU boot loader as the default boot priority.

    And in the UBUNTO boot loader i have GRUB2 wich can now boot Windows 10 and Ubuntu.

    I installed the Grub Costumizer in UBUNTO and i already changed the label for the Windows 10 entry, and set it to default.


    All there's left to do is to add LibreElec to GRUB2.


    I tried to add it selecting the LibreElec partition in it's nvme drive in GRUB COSTUMIZER, but i get the error "unable to set the boot sequence - check parameters"

    I found some instructions to add OpenElec and LibreElec on this forum and others, but the way to do it was much more command line based and there are some variables that i don't know how to adjust to my system.


    Quote
    1. menuentry "LibreELEC" {
    2. set root=(hd0,5)
    3. linux /KERNEL boot=/dev/sda5 disk=/dev/sda6 quiet
    4. }


    The set root line, if the disk is listed as /dev/sda5 as the case above, is "hd0,5" , in my case i have:

    /dev/nvme1n1p1 ->system, vfat

    /dev/nvme1n1p2 ->storage, ext4

    What do i place on the "set root" ?

    Also, in grub customizer, how do i add LibreElec? "Linux", "Chainloader" , "Other" or "Script Code" ?

    I feel i'm close, just need these two questions answered! Thanks in advance!

    On grub boot menu press 'c' to get the grub console, then

    Code
    search --file /KERNEL

    Grub prints disk and partition number of the LibreELEC system partition.

    I've no experience with grub customizer. Just create /boot/grub2/custom.cfg and insert the menuentry.