LG Ultrafine USB-C to RX580 HDMI not working
Which LG UltraFine 4K display do you have? You said it has a Thunderbolt port, so it must be the new 24" 3840x2160 instead of the old USB-C only 21" 4096x2304. They both should work with USB-C input.
Today I received the Huawei VR2, hooked it up to a DP port of the RX580, the USB to the iMac and the USB-C to the Ultrafine. Still not working. I get a OS dialog that says "This device cannot be connected. Use a Thunderbolt port instead".
For curiosity I tried the same setup on a late 2013 trashcan and again receiving the same dialog. the display is not recognized with the VR2 cable linked to the RX580.
The trashcan can obviouslly run the display with just a TB3>TB2 adapter but I am trying to make it work on the TB1 iMac through the EGPU
The 27MD5KA-B is the old LG UltraFine 5K which does not support USB-C DisplayPort Alt Mode input. The input must be Thunderbolt.
You need a Blackmagic or Sonnet eGPU with downstream Thunderbolt port to connect the 27MD5KA-B. Or you need a Thunderbolt 3 add-in card between your GPU and the display.
The newer LG UltraFine 5K 27MD5KL-B supports input from USB-C DisplayPort Alt Mode and input from Thunderbolt. The USB-C DisplayPort Alt Mode input supports 4K 60Hz or (5K 39Hz with custom timing). Thunderbolt input is required for 5K 60Hz 10bpc RGB.
Hello, all. Finally I have the Moshi active USB-C>DP cable, as suggested here and in other posts or forums. Plugged it on the TB port of the Ultrafine, but it doesn't work. The current setup is this: iMac TB1 with Apple adapter to Razer Core with RX580 . From DP1 of the RX580 to TB port of the Ultrafine. I have already tried disconnecting, reconnecting, as well as rebooting options. The monitor is also not recognized.
Is it hopeless or what? So please tell me, do I need an Alpine Ridge with a Wacom Link Plus? Or riser? Or an HP G2 Thunderbolt dock?
@monisha_shukla, do you have the 22" LG UltraFine 4K (4096x2304) display (22MD4KA-B) or the 24" LG UltraFine 4K (3840x2160) display (24MD4KL-B)?
Some people reported issues with the Moshi cable (it's bidirectional, not active - no such thing as an active USB-C to DP cable) and the old display.
I would try Wacom Link Plus or Belkin Charge and Sync Cable. They are better than the USB-C to DP cable because they include USB for brightness control, audio, USB ports, camera, etc.
Thunderbolt 3 appears to be the minimum official level supporting 100Hz or 120Hz screens and DP the only cable which is supported for higher Hz levels.
Hacking T2-T1 is something many don't want to do, and yes I tried, but starting at Thunderbolt 3 is probably the least stressful method.
The Startech T3/ Type-C to DP cable is the best cable from a Thunderbolt 3 port IMO.
HDMI is the source of the problems for macOS IMO.