kernel panic after upgrade

Snapshot

Trying to install

I have a kernel panic situation after doing apt upgrade.
I forgot to do autoremove and autoclean. My fault.

apt's autoremove and (auto)clean command only free disk space: not using them is not the cause of your problem.

I dont´t see the option to use another kernel.

Do you see GRUB's menu before the kernel boots? If so, select the "Advanced options for Trisquel" (or something like that) and then another kernel (not the first one that is listed).

I connect the USB, try to install and it says cannot do because kernel is not started.

You chose to directly install from the initial menu, right?

I think the problem is no space in boot partition.
How can I get terminal to do just that?

Boot into the live system, mount the filesystem on your internal disk (the one attached at /boot) and execute 'df ' in a terminal.

I would bet on another problem though: your ext4 filesystem on sda2 looks corrupted ("unable to read superblock"). 'fsck -y /dev/sda2' may be all you need to fix the corruption.