Hi all,

I've published synodeb, a project that runs plain Debian 13 (trixie) on the Synology
DS923+: https://github.com/rylos/synodeb (I'm the author, GPL-2.0).

Boot
The NAS keeps booting from its internal DOM with Synology's own GRUB. synodeb adds two
entries next to DSM's (kernel and initrd on synoboot2) after a full backup of the DOM;
an "uninstall" restores it. DSM stays bootable on its own disks, and one command
switches between the two.

Kernel
Mainline 7.3 with the Debian config plus seven small patches, no Synology kernel
sources:
- a platform driver for what the BIOS doesn't describe: bay and USB VBUS power, bay
presence, fan tachometers, the power-off/reboot sequence through the front-panel
microcontroller;
- the ATmega1608 LED controller;
- JMB585 PHY tuning, so the links run at 6 Gb/s;
- the RTC alarm, for scheduled power-on;
- per-bay activity LED triggers;
- a reboot notifier;
- read-only mounting of DSM's btrfs volumes, to copy data off them.

Packages are built for each 7.3.y stable release by a GitHub Action and served from a
signed apt repo. A new kernel that doesn't boot falls back to the previous one by
itself. Module signing is not enforced, so DKMS works.

Install
A script on DSM puts the stock trixie netboot debian-installer on the DOM, with the
module udebs rebuilt from the custom kernel and a preseed for the steps before
network-console. After the reboot you run the normal installer over SSH, and pick
disks, RAID, LVM and filesystems as on any Debian box. No serial console needed; if
you want one anyway, the header pinout is in docs/serial.md.

Userspace
A small daemon handles the fan curves (CPU and disk temperatures), the LEDs, the
buttons and the beeper. NUT runs a DSM-like Safe Mode for a USB UPS, with restart
after AC loss, and there's the hardware watchdog (ACPI WDAT).

Only the DS923+ is supported. The DS723+ and DS1522+ share the platform, but I can't
test them. Feedback and bug reports are welcome.

Linux Device Hacking

Message History

Delivery option(s)