Dobrý den, 
nevím, co dělám špatně:
root@mix:~# lsblk
NAME                 MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda                    8:0    0  1,1T  0 disk
├─sda1                 8:1    0  512M  0 part  /boot/efi
└─sda3                 8:3    0  1,1T  0 part
  └─sda3_crypt       254:0    0  1,1T  0 crypt
    ├─mix--vg-root   254:1    0    1T  0 lvm   /
    └─mix--vg-swap_1 254:2    0 63,7G  0 lvm   [SWAP]
root@mix:~# cat /boot/efi/EFI/debian/grub.cfg
cryptomount -u 61cb768b-62db-4b83-99c1-f4e101f19412
search.fs_uuid c061a3cd-c154-4881-8a71-55c2e778aff2 root lvmid/lTs9Wc-V7ak-5SMV-aMNG-kslH-Ajaa-ZeiDUC/rvmX3v-de1h-Q7Vx-hQsn-7mwl-b06Q-tA2r8M
set prefix=($root)'/boot/grub'
configfile $prefix/grub.cfg
root@mix:~# blkid
/dev/mapper/sda3_crypt: UUID="t0UzCf-UMwW-oK5y-pCq5-kvn2-1RtN-U2AkKg" TYPE="LVM2_member"
/dev/mapper/mix--vg-root: UUID="c061a3cd-c154-4881-8a71-55c2e778aff2" TYPE="ext4"
/dev/sda3: UUID="61cb768b-62db-4b83-99c1-f4e101f19412" TYPE="crypto_LUKS" PARTUUID="9a062dcf-8941-47d8-88d6-d9156ed328cb"
/dev/sda1: UUID="2E1D-8289" TYPE="vfat" PARTUUID="cc1ead8e-fe0b-4d54-b179-604b4e3f0be9"
/dev/mapper/mix--vg-swap_1: UUID="854dcc51-4197-4e86-8742-76e707e221c6" TYPE="swap"
Po rebootu: grub> 
GRUB mám verze 2.02+dfsg1-10.