Huh. When I enable Bluetooth in dietpi-config the resulting process ends with
Setting up bluez (5.66-1+deb12u1) ...
Created symlink /etc/systemd/system/dbus-org.bluez.service → /lib/systemd/system/bluetooth.service.
Created symlink /etc/systemd/system/bluetooth.target.wants/bluetooth.service → /lib/systemd/system/bluetooth.service.
Processing triggers for libc-bin (2.36-9+deb12u7) ...
Processing triggers for man-db (2.11.2-2) ...
Processing triggers for dbus (1.14.10-1~deb12u1) ...
[ OK ] DietPi-Set_hardware | APT install bluez
[ OK ] DietPi-Set_hardware | systemctl enable --now bluetooth
[FAILED] bluetooth enable | Exited with error
So I looked in dmesg and the related output there seems to be this:
[10716.405025] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[10716.405059] Bluetooth: BNEP filters: protocol multicast
[10716.405084] Bluetooth: BNEP socket layer initialized
[10717.258663] Bluetooth: RFCOMM TTY layer initialized
[10717.258684] Bluetooth: RFCOMM socket layer initialized
[10717.258704] Bluetooth: RFCOMM ver 1.11
[10717.272741] Bluetooth: HIDP (Human Interface Emulation) ver 1.2
[10717.272768] Bluetooth: HIDP socket layer initialized
[10717.289407] Bluetooth: HCI UART driver ver 2.3
[10717.289426] Bluetooth: HCI UART protocol H4 registered
[10717.289432] Bluetooth: HCI UART protocol BCSP registered
[10717.289438] Bluetooth: HCI UART protocol ATH3K registered
[10717.289520] Bluetooth: HCI UART protocol Three-wire (H5) registered
[10717.289879] Bluetooth: HCI UART protocol Intel registered
[10717.290117] Bluetooth: HCI UART protocol Broadcom registered
[10717.290160] Bluetooth: HCI UART protocol QCA registered
[10717.290166] Bluetooth: HCI UART protocol AG6XX registered
…but those are not errors, so I guess the error-message must have been sent elsewhere.
I hadn’t even tried using the Bluetooth until now, because I didn’t need to, so that was the behavior on a fresh first attempt.