[EXPERIMENTAL] CoreELEC 22 · samurihl DV build (20260722204012)

⚠️ 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.

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What's changed in this update

This is an incremental update to
v22.0-samurihl-20260722100800
(see that release and its predecessors for the standing feature set: HDR10+ → Dolby
Vision conversion, FEL profile‑7 reconstruction on non‑DV displays, VS10 output on
non‑DV displays, VSVDB override, tone‑mapping target controls, disc‑menu playback +
the disc‑menu review/BC fixes, reference‑player capability registers). The headline
this time: Dolby Vision titles converted to HDR10 by VS10 now stay in HDR10 for the
whole title instead of dropping to SDR a second in — plus a fix so HDR10+ → Dolby
Vision conversion keeps working when you also have VS10 HDR10→DV enabled.

⚠️ 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.

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🎬 Dolby Vision → HDR10 no longer drops to SDR

If you watch Dolby Vision on an HDR10 display with Settings → System → "DV VS10
for DV video" set to HDR10, playback used to flash HDR10 for about a second (you'd
even see the HDR10 pop‑up on the TV) and then fall back to 8‑bit SDR for the rest of
the title. It hit both profile‑7 FEL and profile‑8.1 material, and it happened
on every box — AM9 Pro (S928X), Ugoos SK4 (S6) and AM6B+ (G12B) alike.

Now the picture comes up in HDR10 and stays there — full 12‑bit, BT.2020 — for the
whole title, with the complete Dolby Vision engine still running underneath (FEL
enhancement‑layer merge and dynamic tone‑mapping). Validated on‑device: the TV holds
4K 422 BT.2020 12‑bit HDR start to finish, with no mid‑playback drop to SDR.

Why it was broken: the Dolby Vision core stays engaged even when VS10 is only using it
to output HDR10. The kernel's HDMI colour‑format chooser saw "DV core on" and forced the
wire into the Dolby Vision tunnelling format (8‑bit), so the moment Kodi did its
normal refresh‑rate switch a second into playback, the display re‑negotiated at 8‑bit —
and an 8‑bit link can't carry HDR10, so the TX dropped the signal to SDR and never
recovered. The fix keys that decision on what VS10 is actually outputting: only use
the Dolby Vision 8‑bit tunnel when the output is genuine Dolby Vision, and keep the
native 12‑bit HDR10 link for HDR10/SDR output — exactly like native HDR10 playback.
(Kernel change; applies to the whole Amlogic HDMI stack, so it covers every affected
board.)

🌈 HDR10+ → Dolby Vision conversion no longer blocked by VS10 HDR10→DV

If you had HDR10+ → DV conversion on and "DV VS10 for DV video" set to convert
HDR10 → DV, the VS10 mapping won the race and your HDR10+ titles played as a flat
static conversion — the dynamic HDR10+ metadata was thrown away before the decoder could
even see it. (This is why the "Lake" HDR10+ demo looked static until you disabled VS10
HDR10→DV.)

Now the HDR10+ → DV path takes precedence: an HDR10+ source is left alone at open so
the decoder can detect its dynamic metadata and synthesise the proper per‑scene RPU. If a
title turns out to be plain HDR10 (not HDR10+), the VS10 HDR10→DV mapping is applied
exactly as before — so nothing regresses for regular HDR10. You no longer have to choose
between the two settings.

🎚️ HDR10+ peak‑brightness source fixed to "Histogram Plus"

The peak‑brightness source selector for HDR10+ → DV conversion is gone; it's now
hard‑wired to Histogram Plus, the percentile‑weighted method that matches the
reference conversions (the same choice p3i and avdvplus make). It was the best option in
every case and the other modes were only ever there for experimentation, so removing the
setting just means one less thing to get wrong. No action needed — existing installs get
the good behaviour automatically.

How to help

The DV → HDR10 fix wants real‑world eyes on an HDR10 (non‑DV) display with "DV
VS10 for DV video" set to HDR10: play Dolby Vision FEL (profile 7) and profile
8.1 titles (files and Blu‑ray, including menus) and confirm the picture stays in HDR10
the whole way through — no flash‑then‑SDR, no drop to 8‑bit, dark detail and highlights
intact. HDR10+ owners: with both HDR10+ → DV and VS10 HDR10→DV enabled, confirm
HDR10+ demos convert with visible dynamic brightness changes rather than a flat picture.
The standing target‑luminance / TrueHD‑sync / menu‑colour checks from earlier releases
still apply. When something misbehaves, grab a debug log
(kodi-send --action=ToggleDebug), note the disc/title, and report it. "Worked
perfectly" reports help too.

Known rough edges (still open)

• VC‑1 discs still don't play (endless busy spinner) — known, open.
• 3D Blu‑rays (MVC) don't decode — known, open.
• A ~1/3‑second stream‑start trim remains at title start (matches stock player).

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Install

• Clean install: flash the Generic *.img.gz (SD/USB via balenaEtcher, or the
  Amlogic USB Burning Tool for eMMC).
• Update in place: drop the *.tar in /storage/.update and reboot.
• Verify your download against the SHA256 sums below before flashing.
• On other Amlogic-no boards (Odroid / Khadas / Radxa): use the *.tar update, or
  your board's own image.

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Source

• CoreELEC (distro): SamuriHL/CoreELEC tag v22.0-samurihl-20260722204012
• Kodi: SamuriHL/coreelec-xbmc tag v22.0-samurihl-20260722204012

Checksums (SHA256)

cf9b52e080aa4e9bd03c2accc9dccfa3ef1491ce60e08d4d0cb41b9332d7c053  CoreELEC-Amlogic-no.aarch64-22.0-Piers-samurihl-EXPERIMENTAL_20260722204012.tar
58a002422846813132c8eb628537f0307a54aba83c3bcb2ec06af9673c44892b  CoreELEC-Amlogic-no.aarch64-22.0-Piers-samurihl-EXPERIMENTAL_20260722204012-Generic.img.gz