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Software stack

Everything Sony loaded onto the HAP-Z1ES / HAP-S1, derived from the published Sony GPL source release (mandatory under GPL terms) and from observed banners on a live device.

Build system / base distribution

  • OpenWrt trunk r35385 (snapshot circa 2013).
  • This makes the HAP a slightly customized OpenWrt device. Most of the conventions (/etc/init.d/, UCI configuration, opkg package management) should be familiar to anyone who has worked with router firmware.

Bootloader and kernel

  • U-Boot 2012.04.01 with Sony patches. Lives on an SoC-side SPI-NOR (M25P32, 4 MB), alongside the kernel — not on the HDD. The rootfs is on a separate NAND chip (Freescale GPMI), /dev/mtdblock2, writable JFFS2. See 07-firmware.md / 10-uart-console.md.
  • Linux 3.0.35 with Sony patches and Freescale BSP. Released 2012, vintage Freescale i.MX6 kernel.
  • Both kernel and U-Boot sources are in the oss.sony.net GPL bundle, including the patch files.

Userland packages (extracted from GPL release)

Category Package Version Notes
Init system OpenWrt procd + netifd + ubus + uci + libubox 2012-12-20 era Standard OpenWrt boot
Core utils busybox 1.19.4
Device manager udev 173
File sharing samba 3.0.37 SMBv1 by default, switchable up to 3.1.1 via Special Mode (firmware ≥18777R)
SSH dropbear 2012.55 Built into firmware but not started by default — key lever for getting root
HTTP server lighttpd 1.4.35 Serves both port 60100 (UPnP description) and port 60200 (JSON-RPC API)
DNS / DHCP dnsmasq 2.62
Bluetooth bluez 3.36 Bluetooth A2DP receiver mode
Package manager opkg (snapshot) OpenWrt's package manager
Audio framework alsa-lib + alsa-utils 1.0.24.x
Audio codecs FLAC 1.2.1, libvorbis 1.2.3
Playback engine gstreamer + base/good/bad/ugly/python 0.10.36 Obsolete since ~2013 (GStreamer 1.x is current)
Freescale GStreamer gst-fsl-plugins 3.0.5 i.MX6 hardware acceleration
Freescale userland imx-lib 12.08.00 i.MX6 vendor library
File-share over NFS unfs3 NFS server (purpose unclear — possibly internal use only)
Disk partitioning gptfdisk
Scripting python 2.7.3 The control daemon runs on this
Web framework web.py 0.37 Powers the JSON-RPC daemon
OSC pyOSC Likely used for internal IPC between Python daemon and GStreamer
Database (1) sqlite 3.27 The music library metadata store — confirmed by direct disk read 2026-06-02 (/data/*.db, format ver 14.00). See 09-disk-layout.md
Database (2) tokyocabinet 1.4.47 In the GPL bundle, but NOT the library DB (earlier assumption corrected). Actual on-device use unknown
Metadata reader libmediainfo 0.7.81 Music file tag extraction
Front-panel UI DirectFB 1.4.17 Direct framebuffer GUI (no X11)
IPC dbus 1.4.14
Crypto openssl 1.0.2u

The Sony-custom pieces

These are not in the GPL bundle (because they're either proprietary or trade secrets). The codename across all of them is "forza" (Italian: force).

  • forza_snd_driver — the custom ALSA kernel module that glues GStreamer to the FPGA + SHARC + PCM1795 chain. Sony's GPL obligation does cover this (it's a kernel module, GPL-derived), and the source IS in the bundle. Reading this is the entry point for understanding the audio path programming.
  • hapmcr (inferred name) — the control daemon binary running on Python 2.7 + web.py + lighttpd, exposing the JSON-RPC API on port 60200. Not in the GPL bundle. Closed.
  • The GStreamer playback elements that handle DSD playback, gapless transitions, the DSEE-HX upscaler, and the proprietary HAP-format decoder. Not in the GPL bundle.
  • The UPnP daemon serving MusicConnect:1 and the iOS-app-facing protocol. Not in the GPL bundle.
  • The library indexer that parses incoming files dropped on the SMB share, extracts metadata via libmediainfo, and builds the SQLite library database (/data/*.db; runs as root). Not in the GPL bundle.
  • The HAP firmware-update tool that consumes the .SonyAP blob. Not in the GPL bundle.
  • The FPGA bitstream. Not in the GPL bundle (and would be irrelevant in source form — it's already compiled to FPGA logic).

Audio path data flow (best current understanding)

   Music file (FLAC/DSF/WAV/etc.)
            │
            │ SMB1 PUT to HAP_Internal share
            ▼
   /mnt/internal/storage/<Artist>/<Album (year)>/file.flac
            │
            │ indexer scans, writes SQLite library DB
            ▼
   /data/master.db + /data/hdd_browse*.db  (confirmed 2026-06-02)
            │
            │ Playback request via JSON-RPC or front panel
            ▼
   Python control daemon (web.py on lighttpd)
            │
            │ DBus / OSC / direct call?
            ▼
   GStreamer pipeline (filesrc → flacdec → forza_snd_sink)
            │
            │ Sony Forza ALSA driver
            ▼
   I²S → FPGA → SHARC → 2× PCM1795 → analog out

The Python daemon does the orchestration; GStreamer does the decoding; the Forza driver hands samples to the FPGA; the FPGA handles clock recovery and routes to the SHARC + DACs. The DSEE-HX upsampling and DSD remastering likely happen inside the SHARC, not in GStreamer.

Implications for the modernization plan

  • The control plane is editable without recompiling C. Python + web.py on lighttpd means: get a shell, edit a .py file, restart lighttpd, ship a new feature. This is enormously favorable for Phase 4 — we don't need to rebuild a kernel module to add Tidal support.
  • GStreamer 0.10 is dead. To integrate modern streaming (librespot, Tidal SDK, Roon endpoint), we'll likely need to either backport elements or run a parallel GStreamer 1.x stack alongside the original, or replace the playback engine entirely with MPD. Each option preserves the Forza driver, which is the part that matters for sound quality.
  • The init system is OpenWrt-standard. Enabling Dropbear SSH at boot is a one-line edit in /etc/init.d/ once we have shell. Same for adding our own daemon.
  • Samba 3.0.37 is ancient and vulnerable. Anyone running their HAP on a network with untrusted devices should already worry. Upgrading Samba is a Phase 3 deliverable.
  • DirectFB UI on the front panel means we can theoretically replace the on-device UI without driving a separate display server.

Open questions

  1. Where exactly is the rootfs stored? Answered 2026-06-02/03. The HDD holds no rootfs (only /data SQLite catalog + /mnt/internal music). The OS is on-board: U-Boot + kernel on SPI-NOR M25P32 (4 MB), rootfs on NAND (GPMI), /dev/mtdblock2, writable JFFS2 (from the GPL kernel cmdline root=/dev/mtdblock2 rootfstype=jffs2). Exact MTD offsets confirm at first cat /proc/mtd. See 09-disk-layout.md / 10-uart-console.md.
  2. How is GStreamer driven by the Python daemon — via DBus, via OSC (hence the pyOSC package), or via direct subprocess?
  3. What's in /etc/inittab or the OpenWrt procd boot sequence?
  4. Are there cron jobs that periodically scan the SMB share or check for firmware updates?

All answered the moment we have UART shell.