External MDP screen works on 10.14.2, but not on 10.14.6 - any ideas?

[Ploki]

My main display is UltraFine 4K, i wanted to add an old PackedPixels gen1 (MDP input) to it, via CalDigit TS3+ DisplayPort.
The boot logo displays normally, then image becomes garbled.

Running Mojave 10.14.6.

It doesn't matter whether Ultrafine 4K is connected or not.
Display is detected by macOS post boot, but changing resolution doesn't fix anything, there's no way that I know of to make it display a picture.

I have options that aren't free:
- getting USB-C to MiniDP + USB adapter from packedpixels (30€)
- getting a cheaper USB-C to MiniDP cable off ebay (~10€)

However, i can't be sure any will really work + I want to keep another Thunderbolt3 port on the mini vacant for now because i have other plans for it.

i'll try tomorrow with my MBP 13" as well... It works fine on gf's 2012 via TB2 port directly

https://imgur.com/a/I4V8XT4

 

[Ploki]

on my "dump" system, i did some RGB EDID override, then installed SwitchResX, then REMOVED switchresX, and now it's somehow (well, perfectly) working in HiDPI mode.

Problem is, i cant get it to replicate on my main drive. I've wasted a day on this, if anyone has any ideas...

 

[Ploki]

update:
it works perfectly on two systems i have on external drives,even without switchresX or any terminal tricks, but they're both. 10.14.2
can't make it work on 10.14.6 or 10.14.5 at all.

so it's a macOS issue.
great.

 

[Ploki]

Called apple, they said it's not a hardware issue, and that i need to speak with display manufacturer... :S

 

[Ploki]

bought a LMP USB-C to MiniDP converter.
Lost a Thunderbolt3 port, but display now works as it should. Odd... and annoying, but hey, at least it works