ls -l /mnt/runimg/
total 18797568
-rwxrwxrwx+ 1               99   99 4555014144 Jan  7 22:32 2019-04-08-raspbian-stretch_chroot.img
-rwxrwxrwx+ 1 systemd-timesync   98 3481272320 Jan  2 10:18 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 21:00 2019-09-26-raspbian-buster_jin.img
drwxrwxrwx+ 1 root             root        160 Dec 19 22:41 bak
-rw-rw-rw-+ 1               99   99 1728053248 Jan 13 11:43 readynas_compile_tool2.img
-rw-rw-rw-+ 1               99   99 2173698048 Jan  8 23:25 readynas_compile_tool.img
pi@raspberrypi48:~ $ sudo mkdir -p ~/rpi_mnt
pi@raspberrypi48:~ $ sudo losetup -f -P --show /mnt/runimg/2019-09-26-raspbian-buster_jin.img
/dev/loop0
pi@raspberrypi48:~ $ sudo mount /dev/loop0p2 -o rw ~/rpi_mnt
pi@raspberrypi48:~ $ cd ~/rpi_mnt
pi@raspberrypi48:~/rpi_mnt $ sudo mount --bind /dev ~/rpi_mnt/dev/
pi@raspberrypi48:~/rpi_mnt $ sudo mount --bind /sys ~/rpi_mnt/sys/
pi@raspberrypi48:~/rpi_mnt $ sudo mount --bind /proc ~/rpi_mnt/proc/
pi@raspberrypi48:~/rpi_mnt $ sudo mount --bind /dev/pts ~/rpi_mnt/dev/pts
pi@raspberrypi48:~/rpi_mnt $ sudo mkdir -p  /media/netdir/source/raspberrypi/4-09
pi@raspberrypi48:~/rpi_mnt $ sudo mkdir -p  ~/rpi_mnt/mnt/compile
pi@raspberrypi48:~/rpi_mnt $ sudo mount  --bind  /media/netdir/source/raspberrypi/4-09 ~/rpi_mnt/mnt/compile
pi@raspberrypi48:~/rpi_mnt $ cd ~/rpi_mnt
pi@raspberrypi48:~/rpi_mnt $ sudo chroot . bin/bash
root@raspberrypi48:/# 
root@raspberrypi48:/# dtoverlay=pi4-disable-wifi
root@raspberrypi48:/# dtoverlay=pi4-disable-bt
root@raspberrypi48:/# date
Sun 26 Jan 2020 09:06:06 PM JST
root@raspberrypi48:/# 
root@raspberrypi48:/# 
root@raspberrypi48:/# compile finish
bash: compile: command not found
root@raspberrypi48:/# exit
exit
pi@raspberrypi48:~/rpi_mnt $ cd 
pi@raspberrypi48:~ $ sudo umount  ~/rpi_mnt/mnt/compile
pi@raspberrypi48:~ $ sudo umount  ~/rpi_mnt/dev/pts
pi@raspberrypi48:~ $ sudo umount  ~/rpi_mnt/proc
pi@raspberrypi48:~ $ sudo umount  ~/rpi_mnt/sys
pi@raspberrypi48:~ $ sudo umount  ~/rpi_mnt/dev
pi@raspberrypi48:~ $ sudo umount  ~/rpi_mnt
pi@raspberrypi48:~ $ sudo losetup -d  /dev/loop0
pi@raspberrypi48:~ $