Somehow when I put the following
mount /dev/mmcblk0p4 /mnt/debian
the phone starts to load the cpu 75-100%
I attached the phone as USB storage to Ubuntu and formatted the mmcblk0p4 as ext2. It was ext3
rebooted and again
mount /dev/mmcblk0p4 /mnt/debian
seems it is a bit better.
after that again "cp"
and following your advice in new terminal I entered "df -h"
.... useful
Now the problem I see is that the "cp" is doing too slow the things. It was copied just 40-45 Mb in about 7-9 minutes. Wow! It is too slow.
Then I get another idea.
Is it possible to mount the img file in Ubuntu? Then to mount with BootMenu the whole phone part (all its pertitions) to Ubuntu and to to this "cp" probably quicker than now.

P.S. CP process started at 10:25. Now 11:18 the mmcblk0p4 is with 347,8M of data. To get all 2,1G I will need to wait almost 5 hours. Woww