How exactly display grub menu on trisquel's boot?

Ok. I get it pressing Shift during boot.

But I see only one option "Trisquel"

I have two kernels. How to make them all visible in grub?

$ ls /boot
abi-4.4.0-119-generic retpoline-4.4.0-119-generic
abi-4.4.0-128-generic retpoline-4.4.0-128-generic
config-4.17.3-gnu System.map-4.17.3-gnu
config-4.4.0-119-generic System.map-4.4.0-119-generic
config-4.4.0-128-generic System.map-4.4.0-128-generic
grub vmlinuz-4.17.3-gnu
initrd.img-4.17.3-gnu vmlinuz-4.4.0-119-generic
initrd.img-4.4.0-119-generic vmlinuz-4.4.0-128-generic
initrd.img-4.4.0-128-generic

# LANG=en-us update-grub
Generating grub configuration file ...
Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported.
Found linux image: /boot/vmlinuz-4.17.3-gnu
Found initrd image: /boot/initrd.img-4.17.3-gnu
Found linux image: /boot/vmlinuz-4.4.0-128-generic
Found initrd image: /boot/initrd.img-4.4.0-128-generic
Found linux image: /boot/vmlinuz-4.4.0-119-generic
Found initrd image: /boot/initrd.img-4.4.0-119-generic
done

ok. i found my other kernels in option "Advanced options" in grub