I big thank you for this, works like a charm.

I made it even simplier as I just want my home be mounted on my sdcard, and I know it is here.

[nemo@localhost ~]$ cat /usr/sbin/mount-sd-home.sh
#!/bin/bash
ACTION=$1
if [ "$ACTION" = "add" ]; then
if [ $(mount | grep -c /mnt/sdhome) != 1 ]; then
mount -o noatime,rw,autodefrag /dev/mmcblk1p1 /mnt/sdhome
mount -o bind /mnt/sdhome/.home /home/nemo
mount -o bind /mnt/sdhome/.android /data/sdcard
fi
else
umount /data/sdcard
umount /home/nemo
umount /mnt/sdhome
fi

[nemo@localhost ~]$ cat /lib/systemd/system/mount-sd-home.service
[Unit]
Description=Handle home on sdcard
After=local-fs.target
RequiresMountsFor=/home

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/sbin/mount-sd-home.sh add
ExecStop=/usr/sbin/mount-sd-home.sh remove

[Install]
WantedBy=multi-user.target

Everything seems to work:
- ambiences
- new pictures and videos that I take are here and browsable
- settings are persited between reboots


A question, how did you pick the dependecies ?
(After=local-fs.target
RequiresMountsFor=/home)

Is there a doc somewhere I could look at to understand the boot process ?

Regards,
Franck