sudo mkdir -p /mnt/runimg
pi@raspberry4:~ $ sudo mount --bind /media/netdir/raspbrreyPi/mnt_runimg    /mnt/runimg
pi@raspberry4:~ $ ls -l /mnt/runimg/
total 24593408
-rwxrwxrwx+ 1               99   99 4555014144 Jan  7 22:32 2019-04-08-raspbian-stretch_chroot.img
-rwxrwxrwx+ 1 systemd-timesync   98 3481272320 Mar 23 22:09 2019-04-08-raspbian-stretch-make-new.img
-rwxrwxrwx+ 1 root             root 3481272320 Dec 30 09:55 2019-04-08-raspbian-stretch-make-old.img
-rwx------+ 1               99   99 3829399552 Jan 26 21:38 2019-09-26-raspbian-buster_jin.img
-rw-r--r--+ 1 root             root 5934940160 Apr 13 21:59 2020-02-13-raspbian-buster_jin-make.img
drwxrwxrwx+ 1 root             root        160 Dec 19 22:41 bak
-rw-rw-rw-+ 1               99   99 1728053248 Mar 25 22:50 readynas_compile_tool2.img
-rw-rw-rw-+ 1               99   99 2173698048 Jan  8 23:25 readynas_compile_tool.img
pi@raspberry4:~ $ sudo mkdir -p ~/rpi_mnt
pi@raspberry4:~ $ sudo losetup -f -P --show /mnt/runimg/2020-02-13-raspbian-buster_jin-make.img
/dev/loop0
pi@raspberry4:~ $ sudo mount /dev/loop0p2 -o rw ~/rpi_mnt
pi@raspberry4:~ $ cd ~/rpi_mnt
pi@raspberry4:~/rpi_mnt $ sudo mount /dev/loop0p1 -o rw~/rpi_mnt/boot/
mount: /dev/loop0p1: can't find in /etc/fstab.
pi@raspberry4:~/rpi_mnt $ sudo mount --bind /dev ~/rpi_mnt/dev/
pi@raspberry4:~/rpi_mnt $ sudo mount --bind /sys ~/rpi_mnt/sys/
pi@raspberry4:~/rpi_mnt $ sudo mount --bind /proc ~/rpi_mnt/proc/
pi@raspberry4:~/rpi_mnt $ sudo mount --bind /dev/pts ~/rpi_mnt/dev/pts
pi@raspberry4:~/rpi_mnt $ sudo mkdir -p  /media/netdir/source/raspberrypi/4-08_new_raspi
pi@raspberry4:~/rpi_mnt $ sudo mkdir -p  ~/rpi_mnt/mnt/compile
pi@raspberry4:~/rpi_mnt $ sudo mount  --bind  /media/netdir/source/raspberrypi/4-08_new_raspi ~/rpi_mnt/mnt/compile
pi@raspberry4:~/rpi_mnt $ cd ~/rpi_mnt
pi@raspberry4:~/rpi_mnt $ sudo chroot . bin/bash
root@raspberry4:/# 
root@raspberry4:/# ls -l
total 76
drwxr-xr-x   2 root root  4096 Feb 14 01:00 bin
drwxr-xr-x   2 root root  4096 Mar 21 13:49 boot
drwxr-xr-x  18 root root  4020 Apr 13 22:06 dev
drwxr-xr-x 108 root root  4096 Apr  1 21:50 etc
drwxr-xr-x   3 root root  4096 Feb 14 00:55 home
drwxr-xr-x  16 root root  4096 Feb 14 00:58 lib
drwx------   2 root root 16384 Feb 14 01:15 lost+found
drwxr-xr-x   2 root root  4096 Feb 14 00:51 media
drwxr-xr-x   3 root root  4096 Mar 21 13:47 mnt
drwxr-xr-x   4 root root  4096 Feb 14 01:01 opt
dr-xr-xr-x 152 root root     0 Jan  1  1970 proc
drwx------   3 root root  4096 Mar 21 13:54 root
drwxr-xr-x   4 root root  4096 Feb 14 00:51 run
drwxr-xr-x   2 root root  4096 Feb 14 01:00 sbin
drwxr-xr-x   2 root root  4096 Feb 14 00:51 srv
dr-xr-xr-x  12 root root     0 Apr 13 21:56 sys
drwxrwxrwt   3 root root  4096 Apr  1 22:52 tmp
drwxr-xr-x  11 root root  4096 Feb 14 01:01 usr
drwxr-xr-x  11 root root  4096 Feb 14 00:51 var
root@raspberry4:/# echo 00:00:00
00:00:00
root@raspberry4:/# date
Mon 13 Apr 2020 10:07:04 PM JST
root@raspberry4:/# 
root@raspberry4:/# 
root@raspberry4:/# compile finish
bash: compile: command not found
root@raspberry4:/# exit
exit
pi@raspberry4:~/rpi_mnt $ cd 
pi@raspberry4:~ $ sudo umount  ~/rpi_mnt/mnt/compile
pi@raspberry4:~ $ sudo umount  ~/rpi_mnt/dev/pts
pi@raspberry4:~ $ sudo umount  ~/rpi_mnt/proc
pi@raspberry4:~ $ sudo umount  ~/rpi_mnt/sys
pi@raspberry4:~ $ sudo umount  ~/rpi_mnt/dev
pi@raspberry4:~ $ sudo umount  ~/rpi_mnt
pi@raspberry4:~ $ sudo losetup -d  /dev/loop0
pi@raspberry4:~ $