truenas-rn426-panel

A front-panel driver that brings the LCD and navigation buttons back to life on a NETGEAR ReadyNAS RN426 (and the related RN526 / RN626X, which share the same front board) running TrueNAS SCALE.

When you install TrueNAS on this hardware, the little front display stays frozen on Booting... forever and the buttons do nothing — because TrueNAS has no driver for NETGEAR's front board. This project is that driver, reverse-engineered from the stock ReadyNAS firmware and reimplemented from scratch in pure Python (no kernel module, no compiled helper).

Companion guide: for getting TrueNAS installed on the RN426 in the first place, see the community write-up TrueNAS installation on ReadyNAS 426 — a step-by-step. This project picks up where that leaves off and restores the front panel.

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What it does

• Drives the 128×32 SSD1305 graphic LCD (it's an LCD panel with an SSD1305-class controller; NETGEAR's code calls it "oled").
• Reads the 5-way navigation buttons (up / down / left / right / center).
• Shows rotating info pages you cycle with the buttons:
  1. Hostname + IP
  2. Pool name, health, capacity
  3. CPU temperature + chassis fan RPM
  4. Uptime + load average
• Auto-sleeps the display after a configurable idle timeout (default 90 s) to avoid image retention/burn-in, and wakes on any button press.
• Installs as a systemd service that survives reboots and TrueNAS updates (registered through TrueNAS's config-DB init scripts, just like a fan-control daemon would be).

How it works (short version)

• The LCD is bit-banged SPI over the Intel Denverton SoC GPIO pads, written directly through /dev/mem (PADCFG_DW0 registers). The P2SB window that exposes those registers is un-hidden with a pure-Python PCI-config write via /dev/port — no helper binary.
• The buttons live on a front-board MSP430 microcontroller on the Intel i801 SMBus; the driver reads its reg 0x04 button bitmap over /dev/i2c. It does not poll i2c (that corrupts the MCU's button scanning over time). Instead it watches the MCU's interrupt line — a Denverton SoC GPIO pad (0xFDC50570) read via /dev/mem — and only reads reg 0x04 when a press is signalled. Interrupt-like responsiveness, entirely in userspace, no kernel module. See docs/buttons-protocol.md.

Full details, register maps, and the reverse-engineering story are in docs/.

Requirements

• A ReadyNAS RN426 / RN526 / RN626X running TrueNAS SCALE.
• python3 + Pillow (python3-pil) and the DejaVu fonts — both ship with TrueNAS SCALE.
• Kernel modules i2c-dev and i2c-i801 (loaded automatically by the installer).
• A pool to install onto (the root filesystem is reset on updates, so the files live on a pool and the service is registered in the config DB).

Install

git clone https://github.com/riplatt/truenas-rn426-panel.git
cd truenas-rn426-panel
sudo ./install.sh /mnt/<your-pool>/rn426-panel

install.sh copies the driver to the given directory, loads the i2c modules, registers a POSTINIT init script in the TrueNAS config DB, and starts the service. See the script for the exact, reversible steps.

To remove it: sudo ./install.sh --uninstall /mnt/<your-pool>/rn426-panel.

Usage

# the service runs automatically; manual control:
sudo systemctl status rn426-panel
python3 rn426_panel.py sleep   # blank the display now
python3 rn426_panel.py wake    # re-init / wake it
python3 rn426_panel.py run     # run the loop in the foreground

RN_SLEEP=120 ...               # env var: idle seconds before sleep (0 = never)

Customize the pages by editing the page_*() functions and the PAGES list in rn426_panel.py.

Important gotchas

• i2c bus numbers are not stable across reboots — the i801 and iSMT SMBus adapters can swap between i2c-0 and i2c-1. The driver finds the i801 bus by name, so don't hard-code it.
• Never write the MSP430's reg 0x02 (its LED/control register). On this firmware that register also gates button scanning; once you disable it, the buttons stop reporting and only a full power-cycle recovers them — a warm reboot is not enough (the front board is on standby power). This driver is strictly read-only toward the MCU. If your buttons are dead, do a cold power-off/on once.
• The LCD's EN line gates panel power, so waking from sleep does a full re-init rather than just sending display-on.

Porting to other ReadyNAS models

The approach (RE the stock firmware's oled_probe / spi_send / i2cfb_reporter, then drive the pads via /dev/mem) generalizes. The per-model GPIO pad map lives in the firmware (look for the rn426_8 / rnx16 config structs). See docs/porting.md.

License

MIT — see LICENSE. Not affiliated with or endorsed by NETGEAR or iXsystems. Use at your own risk; this pokes SoC registers directly.