⚠️ EXPERIMENTAL · UNSUPPORTED · USE AT YOUR OWN RISK

This is an unofficial, experimental CoreELEC 22 build. It is NOT an official
CoreELEC release and it is NOT a supported CE22 port. I am not a CoreELEC 22
port maintainer, and I will not be providing support, bug fixes, updates, or
ongoing maintenance for this build.

The only purpose of this build is to give Amlogic AM9 Pro-class users a more
complete Dolby Vision experience than stock CoreELEC 22, by carrying a set of
custom Kodi features I built for my own device. That is the entire scope.

READ THIS BEFORE YOU FLASH ANYTHING

• USE ENTIRELY AT YOUR OWN RISK. There is no warranty of any kind, express
  or implied. It may fail to boot, misbehave, break Dolby Vision, or do nothing
  useful on your hardware.
• BACK UP YOUR CURRENT INSTALLATION FIRST. Take a full CoreELEC backup
  (Settings → CoreELEC → Backup) and/or image your existing boot media before
  you install anything from here. Assume you may have to restore it.
• Prefer a SEPARATE SD card or USB stick you can boot from, instead of
  overwriting a working internal (eMMC) install.
• Do NOT report problems with this build to the CoreELEC team or forums.
  This is not their build; it is not their responsibility. Do not ask them to
  support it.
• I am also not offering support. If it breaks, you keep both pieces.

By downloading or using any file in this release you accept all of the above.

Install

• Clean install (recommended): flash the *.img.gz to an SD card or USB with
  balenaEtcher (or the Amlogic USB Burning Tool for eMMC), then boot from it.
• In-place update: copy the *.tar to the /storage/.update folder on an
  existing CoreELEC install and reboot. (Back up first — see above.)
• Verify your download against the SHA256 sums below before flashing.

What's changed in this update

This is an incremental update to
v22.0-samurihl-20260828133811
(see that release and its predecessors for the standing feature set: Blu‑ray disc
menus, HDR10+ → Dolby Vision conversion, DV → HDR10 that stays in HDR10, FEL
profile‑7 reconstruction on non‑DV displays, VS10 output on non‑DV displays, VSVDB
override, tone‑mapping target controls, disc‑stated menu detection and episode
lists).

This release exists for one reason: Dolby Vision could play to a completely black
screen. If you have hit that — the disc spins, the box looks perfectly healthy, and
the television shows nothing — this is the fix.

⚠️ Still experimental and completely unsupported — see the disclaimer above.
Back up your current install before flashing.

Dolby Vision still requires dovi.ko (the CE22 5.15 build) installed on your
device — it is not bundled; install it yourself as on stock CoreELEC 22. You do
not need to modify it — this build corrects it automatically at boot.

⚫ Fixed: Dolby Vision playing to a black screen

The symptom. Dolby Vision playback produces no picture at all — not the film, not
a Blu‑ray menu, nothing. Everything you can check says the box is fine: the video
decodes at full rate with zero dropped frames, the Dolby Vision core reports itself
engaged, the HDMI link is up, and the display's Dolby Vision capabilities read back
correctly. It comes and goes between reboots, which makes it maddening to pin down.

The cause. A Dolby Vision picture has to leave the box over a link configured
specifically for it — 8‑bit RGB for television‑led Dolby Vision. That link format is
chosen only when the display mode actually changes. When a Dolby Vision title starts
at the refresh rate the interface is already running at, there is no mode change,
so the link keeps whatever format the interface was using — commonly 12‑bit 4:2:2 —
while the box simultaneously tells the television "this is Dolby Vision". The
television switches into Dolby Vision and receives something that isn't. Black
screen.

Whether you hit it came down to whether some earlier mode change happened to have
left the link in the right format. That is why it looked random, and why it could
follow you across builds.

The fix. The player now sets the link format explicitly when Dolby Vision
engages, using controls the driver already provided and that nothing had been using.
Deliberately without forcing a mode change — re‑clocking the display at a mode it
is already running is the exact behaviour that causes the Blu‑ray menu blackouts this
build has fixed before, and that gate is untouched here.

Honesty about how long this has been there. This is not a regression introduced
by the last release. The failure was reproduced deterministically on the previous
release as well, and almost certainly affects earlier ones. It has been latent for a
while and simply depended on luck at boot.

⚫ Fixed: Dolby Vision signalling left stuck on after playback

A second, separate fault found along the way. When Blu‑ray disc playback holds the
Dolby Vision signal across menu and title segments — which this build does on purpose,
so your television doesn't re‑sync on every segment — the "switch back to SDR"
message could be swallowed and then never sent, because by the time it was due the
Dolby Vision core had already shut down.

The result is a television left in Dolby Vision mode being fed ordinary SDR picture:
everything black, including the Kodi interface, and it survives stopping playback,
restarting Kodi, even power‑cycling the HDMI link. Only a full reboot cleared it.

The box now sends that switch‑back itself when the core shuts down. If you have ever
had to reboot to get your picture back after a disc, this was very likely why.

🛠️ Under the hood

A timing guard added upstream to let the Dolby Vision core settle before powering
down was, through a units slip, waiting five milliseconds where it meant five
seconds — shorter than a single iteration of its own loop, so it never waited at all.
It now waits a bounded 200 ms, and skips the wait entirely during a disc session,
where the Dolby Vision core is deliberately held engaged and waiting would only add
delay to every menu‑to‑title transition.

✅ What was tested, and what wasn't

Verified on an AM9 Pro, against a reproduction that fails 100% of the time on the
previous release:

• Dolby Vision file playback — the link now comes up 8‑bit RGB with Dolby Vision
  signalled, where before it stayed 12‑bit 4:2:2 and black.
• Blu‑ray disc, including the BD‑J menu — menu and feature both play, video
  advancing normally.
• ISO playback — confirmed working by the reporter.
• Player‑led (low‑latency) Dolby Vision — confirmed working by the reporter. The
  fix requests a different link format for that mode, so it exercises a genuinely
  different branch rather than repeating the television‑led path.
• Both link formats confirmed at the far end of the cable, by an HDFury VRROOM
  reporting what it actually receives rather than what the box believes it is sending:
  RGB 8b DV in television‑led mode, 422 BT2020 12b LLDV in player‑led. Each matches
  what the fix asks for in that mode.
• The Blu‑ray menu behaviour is unchanged. The mode‑change suppression that stops
  menu blackouts still engages exactly as before across menu and title segments; this
  was checked explicitly rather than assumed.
• No side effects on the interface. After playback the desktop returns to its
  normal format, and non‑Dolby‑Vision video correctly goes back to 12‑bit — the forced
  format is not left stuck on.
• The Dolby Vision teardown fix was confirmed in the kernel log, including the HDMI
  driver's own acknowledgement that the switch‑back was sent.

Not tested: dual‑layer FEL playback and HDMI hotplug recovery — both unchanged by
this release, but they are the paths most exposed to display‑format handling, so they
are worth a look if you exercise them.

Source

• CoreELEC (distro): SamuriHL/CoreELEC tag v22.0-samurihl-20260830205205
• Kodi: SamuriHL/coreelec-xbmc tag v22.0-samurihl-20260830205205

Checksums (SHA256)

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0c2063dfa366383c6de18c85b04d7936e1a3a5d57ccda89002f1719ef94a3ea0  CoreELEC-Amlogic-no.aarch64-22.0-Piers-samurihl-EXPERIMENTAL_20260830205205-Generic.img.gz