This script is based on the one written by scawp - https://github.com/scawp/Steam-Deck.Mount-External-Drive - and a fork by flavioislima - https://github.com/flavioislima/Steam-Deck.Mount-External-Drive.git
Configuration to Auto-Mount External USB SSD on the Steam Deck
A udev rule is added to /etc/udev/rules.d/99-external-drive-mount.rules
which calls systemd /etc/systemd/system/external-drive-mount@[sda1|sda2|sdd1|etc].service
that then runs Valve's /usr/lib/hwsupport/sdcard-mount.sh to Auto Mount any plugged in USB Storage Device.
/etc/fstab is not required for mounting in this way, (however if a Device has an fstab entry these scripts will still work)
The External Drive(s) will be Auto-Mounted to /run/media/deck/[LABEL] eg /run/media/deck/External-ssd/ if the Device has no label then the Devices UUID will be used eg /run/media/deck/a12332-12bf-a33ab-eef/
Drive requires prior formatting (currently tested with NTFS, Ext4, btrfs, NOTE: btrfs mounts with incorrect ownership, TODO). All Partitions will be Mounted on Boot and /or On Insert.
In Konsole type curl -sSL https://raw.githubusercontent.com/araujorm/Steam-Deck.Mount-External-Drive/master/curl_install.sh | bash
a sudo password is required (run passwd if required first)
sudo rm /etc/udev/rules.d/99-external-drive-mount.rules
sudo rm /etc/systemd/system/external-drive-mount@.service
sudo udevadm control --reload
sudo systemctl daemon-reload
This will probably have bugs, so beware! log bugs under issues!