A few more questions

[Ralf Mardorf]

Hi,

before you follow my following advices, wait until another subscriber
confirms that I didn't made a mistake by accident.

Run

  $ sudo -i
  # apt update -qq && apt install gparted util-linux
  # umount /dev/sdb1
  # umount /dev/sdb2
  # umount /dev/sdb3
  # umount /dev/sdb4
  # gparted

on the upper right corner there's a selection box.
Ensure that /dev/sda is the drive with around 40G, including a ext4
file system and the / mount point. If so, select /dev/sdb and ensure
that this is drive providing around 80G and that it does _not_ include
an ext file system and that _nothing_ is mounted. If it shouldn't be
like that _stop_. If everything should be ok, then continue with

  Device -> Create partition table...

to erase the disk and to create a msdos partition table again.
After that

  Partition -> New

Create a primary ext4 partition and when finished close gparted.

  # mkdir /mnt/new_home
  # mount /dev/sdb1 /mnt/new_home/

Now close all applications, excepted of the terminal and don't
do anything else with your computer, just run

  # ls -hAl /home/ /mnt/new_home/

home/ at least contains your home and it should not contain any
directory or file that name starts with a dot. If so, continue with

  # cp --archive /home/* /mnt/new_home/
  # echo $?

The output of echo $? must be 0. If so continue with

  # diff /home/FOO/ /mnt/new_home/FOO | grep Only\ in

where FOO needs to be replaced by one directory after the other. Most
likely there only is one directory, your user's home available.

There must be _no_ output from diff. If so, then most likely everything
went well.

  # exit

Post the output of

  $ blkid /dev/sdb1

and attach /etc/fstab to your email.

Regards,
Ralf