[Sam.Nazarko]

The problem is that the TVs advertise support for unsupported capabilities in their EDID. This is rife with 2009-2012 era sets, as manufacturers seemed to take a one size fits all approach regarding EDIDs for their displays.
So yes, you need to send an RGB signal. Unfortunately, their EDIDs suggest otherwise and this causes a ton of problems. 

Is this them advertising support for 4:4:4 YCbCr but only accepting 4:2:2 YCbCr (along with 4:4:4 RGB?) - or do they support no YCbCr component inputs at certain resolutions and frame sizes? (I'm pretty sure that most consumer gear - until recently - was 4:2:2 720p or 1080i only - so RGB only inputs would have been a nightmare, but if they accepted 4:2:2 YCbCr less so)

I've come across the reverse too - TVs that don't flag all the modes that they accept (some TVs that will accept 50Hz don't report that they will, and mu current UHD set accepts 1080/120p but doesn't EDID flag that it does)

I've not come across a consumer TV that doesn't accept 4:2:2 YCbCr at 720p or 1080i/p - but then I stopped buying Philips TVs in the 80s (and Philips haven't made TVs for a long time now - preferring to license their brand to different manufacturers in different regions)

In the next update on Vero 4K, you will be able to select 'Force RGB' in Kodi instead of manually setting it via the command line. For now, the sysfs approach works, but is rather inappropriate for a 'just works' solution, hence the impending GUI option. 

There's a fix from Mateusz which addresses this, but you'll also need https://github.com/osmc/vero3-linux/comm...a54edbef3c, and it still unfortunately needs manual intervention. 

I've started to notice a few quirks with some sets. As these are reported, we're building a set of fixups based on the EDID parameters we receive. See https://github.com/osmc/vero3-linux/comm...b012fb26d8 for an example. I suspect this will come in handy to deal with flickering issues that sometimes present on some models of LG displays when HDR mode is active. This will allow Vero 4K to adapt to displays and receivers that need to be treated specially without a user having to make any changes out of the box. This is a little bit further off, but for now manual intervention does the trick.

Sam 

 
It certainly gets a whole lot more complicated once you start supporting 4:2:2 YCbCr HDMI 2.0a 2160/50p and 60p HDR modes - which require the higher bandwidth HDMI modes (unlike 4:2:0 2160/50p and 60p modes and the 2160/24-30p modes at 4:4:4 and 4:2:2). Since I switched to HDMI 2.0a high-bandwidth compatible sources I've had to replace a number of HDMI cables, as the increased bandwidth requirements exposed cables that weren't electrically good enough. (£10 replacements fixed the issue)

Plus I guess there are all sorts of potential issues with Metadata/Format flagging for HDR.  I had a hilarious issue where my Sony TV kept flipping from HDR to SDR mode and back again on one source via one combination of cables and splitters...  No idea if headers were being intermittently stripped by the splitter, or if the splitter was futzing EDID, but it was unwatchable. (I do wonder if some Kodi solutions for HDR are currently passing full metadata, or are instead just sending fixed 1000nit stuff) 

I believe that the problem is indeed that they do not tolerate 4:4:4 YCbCr but do advertise it as supported.
Yes -- we've ran in to a few issues with HDR and surprisingly the problem can often be pinpointed to the cable being used itself. 

Unfortunately it only takes one device in the chain to cause problems. This seems to be an issue that will work itself out over time. 

Sam