error: can't find command 'hwmatch' during boot

ello to Every

I need an help to understand how to properly solve an issue happened un an Ubuntu 18.04.

Basically once Ubuntu frezeed and the user was forced to run a Hard Reboot, ubuntu started wit the following error
error:

• can't find command 'hwmatch'

then clicking on the keyboard it asked for a username and password that i don't know.

Trying to understand the configuration i discovered that:

Ubuntu it was installed in efi mode and some security enforcement was done

i found on the /etc/grub.d/40_custom the following line

[QUOTE]#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
set superusers="cmpadmn"
password_pbkdf2 cmpadmin grub.pbkdf2xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
[/QUOTE]

That i suppose is the grub password. For the moment I have fixed the problems commenting out the two line on the 40_custom file and running upgrade-grub but i would like to fix in a proper way re-enabling the security feature applied.

Can someone tell me which is the relation between the hwmatch.mod and the grub password and how i can try to properly fix?

What i have notice is that in some ubuntu this module is

/usr/lib/grub/i386-pc/hwmatch.mod
and

/boot/grub/i386-pc/hwmatch.mod

in others it is just in

/usr/lib/grub/i386-pc/hwmatch.mod like the one that has problem

It is not clear for me, can someone has some experience about this issue?

Thanks in advance