Reinstalling Trisquel mini on X60s fails

After librebooted a X60s, I had no special trouble with Trisquel 8 mini.
A few days ago I started the GRUB configuration in this link page.

https://libreboot.org/docs/gnulinux/grub_cbfs.html

In the middle of this instruction page, there is a item that "How to Modify the GRUB configuration file".
I did not know what I was doing almost at all.
But I followed the below instruction.

> Or, replace it with this, if you are using a Debian-based distribution (e.g., Trisquel GNU+Linux):

cryptomount -a
set root='lvm/matrix-rootvol'
linux /vmlinuz root=/dev/mapper/matrix-rootvol cryptdevice=/dev/mapper/matrix-rootvol:root
initrd /initrd.img

After I replaced it with the above lines, I rebooted the PC. It was different from usual boot. I had to enter the password on the libreboot screen. It did not boot.
I got notices that like "lvm/matrix-rootvol was not found" and "you need load the kernel first". I tried to study GRUB but I changed my mind then tried to reinstall Trisquel mini. First I was going to configure dual booting because I did not want to delete some downloaded things. But while installing, when about the country select page or entering user name etc page, I got a message that "installing failed" "[Emo 5] Input/output error" "Usually it is a problem of CD/DVD or drive, or hard disk. [...] " I tried some ways (delete old partitions, without lvm, without password, with internet connection etc).
After all I tried to reinstall it 7-8 times but I always get the same message and installing fails. The message also always tells me that like "after the message was closed, a bug report will be send then moderators will solve this problem..." but it does not seem that the report was sent. Or rather, somehow the close icon and button do not work, I mean, mostly I cannot close the message by clicking the icon or the button.

I don't know well what information I should write here to get your help. Anyway it seems that reinstalling always fails. It seems that old partitions (?) were already deleted. Because when I boot the PC, sometimes the libreboot screen shows only the graphic (objects hang in the air), in this case any key does not react. Sometimes it shows the items (I think I have to push an arrow key continuously to show the items), and if I choose "Load Operating System", it shows only the libreboot graphic and nothing happens. I have to push the power button long to shutdown.
Would you teach me what I should do to reinstall? Or if possible, I want to use the installed Trisquel mini previously. Thank you.