[Android Q&A, Help & Troubleshooting] Radiolaria:
Hello, i just bring this here up again because i have a similar problem.

I tryed your command and it passed without errors. But without the wished effect.

:/ # mount -o bind /storage/231A-1B1B/DCIM /storage/emulated/0/DCIM

This is the output of "mount"

:/ # mount <
rootfs on / type rootfs (ro,seclabel,relatime)
tmpfs on /dev type tmpfs (rw,seclabel,nosuid,relatime,size=891960k,nr_inodes=163101,mode=755)
devpts on /dev/pts type devpts (rw,seclabel,relatime,mode=600)
none on /dev/memcg type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
none on /dev/cpuctl type cgroup (rw,nosuid,nodev,noexec,relatime,cpu)
none on /dev/bfqio type cgroup (rw,relatime,bfqio)
adb on /dev/usb-ffs/adb type functionfs (rw,relatime)
proc on /proc type proc (rw,relatime,gid=3009,hidepid=2)
sysfs on /sys type sysfs (rw,seclabel,relatime)
selinuxfs on /sys/fs/selinux type selinuxfs (rw,relatime)
/sys/kernel/debug on /sys/kernel/debug type debugfs (rw,seclabel,relatime)
tmpfs on /mnt type tmpfs (rw,seclabel,nosuid,nodev,noexec,relatime,size=891960k,nr_inodes=163101,mode=755,gid=1000)
/dev/block/vold/public:179,65 on /mnt/media_rw/9FE1-FB0F type exfat (rw,dirsync,nosuid,nodev,noexec,noatime,fs=exfat,uid=1023,gid=1023,fmask=0007,dmask=0007,allow_utime=0020,codepage=cp437,iocharset=utf8,namecase=0,symlink=0,bps=512,errors=remount-ro)
/data/media on /mnt/runtime/default/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=1015,multiuser,mask=6,derive_gid,default_normal)
/data/media on /mnt/runtime/read/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,multiuser,mask=23,derive_gid,default_normal)
/data/media on /mnt/runtime/write/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,multiuser,mask=7,derive_gid,default_normal)
/dev/block/mmcblk0p23 on /system type ext4 (ro,seclabel,relatime,discard)
none on /acct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct)
none on /config type configfs (rw,nosuid,nodev,noexec,relatime)
/dev/block/mmcblk0p24 on /cache type ext4 (rw,seclabel,nosuid,nodev,noatime,noauto_da_alloc,data=ordered)
/dev/block/mmcblk0p25 on /data type ext4 (rw,seclabel,nosuid,nodev,noatime,noauto_da_alloc,data=ordered)
tmpfs on /sbin type tmpfs (rw,seclabel,relatime,size=891960k,nr_inodes=163101,mode=755)
/sbin/.magisk/block/cache on /sbin/.magisk/mirror/cache type ext4 (rw,seclabel,relatime,noauto_da_alloc,data=ordered)
/sbin/.magisk/block/system on /sbin/.magisk/mirror/system type ext4 (ro,seclabel,relatime,discard)
/sbin/.magisk/block/data on /sbin/.magisk/mirror/data type ext4 (rw,seclabel,relatime,noauto_da_alloc,data=ordered)
/sbin/.magisk/block/data on /sbin/.magisk/modules type ext4 (rw,seclabel,relatime,noauto_da_alloc,data=ordered)
tmpfs on /storage type tmpfs (rw,seclabel,nosuid,nodev,noexec,relatime,size=891960k,nr_inodes=163101,mode=755,gid=1000)
/data/media on /storage/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,multiuser,mask=7,derive_gid,default_normal)
tmpfs on /storage/self type tmpfs (rw,seclabel,nosuid,nodev,noexec,relatime,size=891960k,nr_inodes=163101,mode=755,gid=1000)
/dev/block/vold/public:179,97 on /mnt/media_rw/231A-1B1B type vfat (rw,dirsync,nosuid,nodev,noexec,noatime,uid=1023,gid=1023,fmask=0007,dmask=0007,allow_utime=0020,codepage=cp437,iocharset=utf8,shortname=mixed,utf8,errors=remount-ro)
/mnt/media_rw/231A-1B1B on /mnt/runtime/default/231A-1B1B type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=1015,mask=6)
/mnt/media_rw/231A-1B1B on /mnt/runtime/read/231A-1B1B type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,mask=18)
/mnt/media_rw/231A-1B1B on /mnt/runtime/write/231A-1B1B type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,mask=18)
/mnt/media_rw/231A-1B1B on /storage/231A-1B1B type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,mask=18)
/mnt/media_rw/231A-1B1B on /storage/emulated/0/DCIM type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,mask=18)

The last line appears after i try to mount the folder. Does anybody k ow what goes wrong here?

Marco