Could someone with a working setup please enable debug logging in CoreELEC, enable debug_dolby with this:
echo 0xFFFF > /sys/module/amdolby_vision/parameters/debug_dolby
and post a dmesg log that plays a DV file?
edit: in tv-led mode
From here this
The reason for the green screen is that when you send the AVI Infoframe to the display to expect a YCbCr signal, PGenerator may still be sending RGB. When a display sees a mismatch like this, you will see a green screen. In fact, you can see this in reverse too, when a display is expecting to receive RGB but in fact receives YCbCr, the screen would be magenta
may help in diagnosing green / magenta screens and flashes that are seen when switching hdmi modes.
Hey Guys, just got my Ugoos AM6B+ and trying to follow posts above as to which CE version to install. Assume 20.5 over 21 for now? Is 21.0-Omega_rc2 generic okay as well?
nm 
… installed 21.0-Omega_rc2 generic and DV is a success!
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Hey again. I’d like to install CE to the eMMc. Followed directions (so I thought). What am I doing wrong? Appreciate any guidance. Thank you.
Starting CoreELEC eMMC installation tool...
System is not supported: g12b_s922x_ugoos_am6b!
CoreELEC:~ # ceemmc -x
Starting CoreELEC eMMC installation tool...
System is not supported: g12b_s922x_ugoos_am6b!
There is NO official support by Team CoreELEC
if you continue to run this tool!
Continue? [y]: y
eMMC size: 0x000747c00000 [32GB]
No CoreELEC installation found on eMMC
Install in dual boot mode, CoreELEC and Android on eMMC
Use CoreELEC data from
[1] current used SD or USB device
[2] existing backup on current used SD or USB device
Install in single boot mode, only CoreELEC on eMMC
Use CoreELEC data from
[3] current used SD or USB device
[4] existing backup on current used SD or USB device
Please choose one option? [1/2/3/4]: 3
Free space of 'partition CE_FLASH': 512MB
Warning: Could not find 'dto' partition!
Could not find 'CE_STORAGE' partition!
Failed to read size of partition 'CE_STORAGE'!
Failed to create new partition table!
I’m on CE 21 RC2.
Nothing, this is intended, see CoreELEC and Dolby Vision
This may change in future, as meanwhile Androids dovi.ko can be stored under CE .storage/ folder, but no prio for now…
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Thank you. Not a biggie… performance is pretty snappy using a mSD card, but wanted snappier with eMMc install 
.
Use the dual boot option
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Thanks for that suggestion. I need to read up on how to go to/from Android OS to CE with dual boot (with both installed to eMMc). Never done it before.
Reboot from nand in coreelec power menu will reboot to android. Coreelec will have priority from cold coot .
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You can install on the emmc, but I would suggest using the dual-boot option.
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The script only lets you install in dual boot mode.
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Is this dovi.ko file still needed if we are installing the new “CoreELEC-Amlogic-ng.arm-21.0-Omega-Generic.img” on to an Ugoos AM6B+? The changelog is unclear.
Changelog says “Other devices on Amlogic-ng like Ugoos AM6+ or Minix NEO U22-XJ (Max) equiped with S922X-J will support Dolby Vision with profile 7 FEL as well.” but it doesn’t say anything about this dovi.ko file whether it needs it or not. Thanks 
yes, you still need it.
What type of “features” should I be seeing here? Reason being is that I can’t get DV to work with my Ugoos AM6b+ even after two install attempts. And the only thing I see there is one slide bar asking me if I want to disable DV or not. Is this the “features” I should be seeing? Please explain what features I should be seeing… thanks
If I can ascertain if the driver has even “loaded” then perhaps I can troubleshoot further on why I get no DV…
You will not see the option to disable DV if your box couldn’t properly load the DV kernel module.
Use Player led only shows up if your TV reports that it can support it in the EDID it passes along. if you can see the option to disable DV, but not player led, it means your TV claimed it can’t handle it.
If you can’t run DV still. Check to see if your TV is set to standard HDMI, vs. “enhanced” HDMI signal for the specific HDMI input. IIRC at least one of my TVs doesn’t behave properly with DV support when that setting is set to standard instead of enhanced. It will likely vary depending on brand of TV.
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Hmmm, oh wow. Thanks for getting me closer to finding the solution to this DV-non playing puzzle.
Okay, so it’s a Sony X85J (in case somebody comes searching) and I got the ugoos plugged into HDMI 4 (HDMI 3 is taken by e-arc to Sony HT-A7000 soundbar). Yes HDMI 4 was on enhanced only so I switched it Enhanced w/ DV and then restarted Kodi and now I got the “Player LED” toggle too. But when I play a DV vid all I get is red & purple splotches even though I do get the DV flag. When I tried toggling the use Player LED to on just to see what would happen, the video is all weird looking plus now again no DV tag on the TV. Swapped out 2.1 HDMI cable with known good 2.1 fiber optic HDMI cable and same thing.
So tried plugging in the ugoos into my Sony HT-A7000 soundbar which has two HDMI inputs. Now I can’t even get any HDR to play nevertheless DV content to play, all I get is no signal from the soundbar even though I tried its various HDMI settings also (enhanced, super enhanced etc). I had used these same 2.1 HDMI cables with my RTX3070 to play HDR content on the TV before so I know they are good. I have no idea why this is happening with this top of the line expensive soundbar.
Regarding the purple/red splotches into HDMI 4 of the X85J TV, is there any other setting in Kodi I can try to make DV finally work? Or is this a brand new $200 paperweight which is incompatible with Sony products? Darn, I am really trying to make this work
I suspect I know what is going on. There appears to be 3 ways of doing tv-led DV. Taking a guess at the setups people are likely to have, only one of these may have been tested so far.
With the HDMI port 4 set to enhanced w/ DV post the outputs of cat /sys/class/amhdmitx/amhdmitx0/dv_cap and cat /sys/devices/virtual/amhdmitx/amhdmitx0/config when you are playing a DV video in tv-led mode and getting the weird colors. Then change the setting of the port back to only enhanced, and post the output of cat /sys/class/amhdmitx/amhdmitx0/dv_cap again.
Now move the ugoos to HDMI port 1 or 2 - I suspect this will make tv-led DV work for you. In any case, again post the output of cat /sys/class/amhdmitx/amhdmitx0/dv_cap, and if tv-led DV works, the output of cat /sys/devices/virtual/amhdmitx/amhdmitx0/config when playing a video in tv-led mode.
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For what it’s worth. I plugged my Ugoos into HDMI 2 set that to enhanced and it’s just working. I also have an X85J TV and tbf the HDMI 3 and 4 ports are really weird. Probably because they are the 120hz ports and for some reason Sony had to treat them differently… Maybe try 2 or 1if you can?
As for my nakamichi sound bar for the Sony A8H TV, if I plug into HDMI 4 it goes crazy in 4K 60hz (ie 600mhz HDMI signal). But flawless on HDMI 3.
AV equipment be weird sometimes…