DP/USB-C/Thunderbolt to HDMI 2.1 4k@120hz RGB4:4:4 10b HDR with Apple Silicon M1-M4 now possible !

[AntibalasHiFi]

Hi, I just got a Samsung QN90D 43", and while I could get 4k 144hz 4:4:4 on my M4 MB Pro on Sequoia, on my Mac Studio M2 Max on Sonoma I can't go above 60hz without 4:4:4 turning off automatically.

 

[Zorast]

I'm using a MacBook M1 Pro with an LG C2 42" and a MOSHOU VMM7100 cable. After I updated my Mac from 14.0 to 15.5 (for using Final Cut Pro), I found I can now get 4K 120Hz HDR 12-bit 4:4:4. I'm not using Better Display, and everything looks great – even better than before.

When I was on 14.0, I could only get 10-bit HDR. Also, I can now control the TV's brightness directly from the Mac, which was disabled before. I'm not sure why this happened. I haven't updated my adapter's firmware since I bought it in Feb 2024.

Unfortunately, I already agreed to sell my C2 to someone about a week ago so I won't be able to use it anymore. 😢

Using the latest macOS was described in the OP:

 

[Zorast]

Hi, I just got a Samsung QN90D 43", and while I could get 4k 144hz 4:4:4 on my M4 MB Pro on Sequoia, on my Mac Studio M2 Max on Sonoma I can't go above 60hz without 4:4:4 turning off automatically.

read the OP. U need latest Firmware from CM. And I think latest macOS

 

[heisen92]

Hello i have this oneugreen adapter, , i checked the fm version and its having the compatible chip, is there some firmware that can be compatible with this ugreen cable?

 

[Worzel_]

How come the colours are all blue tinged when I put it in HDR mode (at 60hz as the option disappears at 120hz)

 

[awer25]

Hello just landed on this thread. I have a macbook pro M4 and I wanted to connect it to my neoG9 59 inches screen. The resolution and framerate is good but the scaling is either too big or too tiny. Can you help me please ? I tried different workaround with betterdisplay but i lost resolution in the better case. Is there a way to keep the best resolution and framerate ? (I am not very techfriendly so please detail the solution if you have one)
Thanks !!!!

I have an M4 Max in a Mac Studio running this same monitor, but I think the M4 Pro MBP has the same capabilities. You don’t have to run it as two monitors, you can get the full resolution (7680x2160) at 120Hz using a quality USB-C to DP 2.0 cable and software like BetterDisplay to allow more resolutions and refresh rates. Over HDMI, I was only able to get 7680x2160@60Hz.

Be sure your monitor is on the newest firmware (currently 1007) and set to DP 2.0 mode (I think default is DP 1.4).

 

[brachacz]

Hi, I got an MBP M4 Max and LG 38GN950, connected through Belkin DP1.4 -> Thunderbolt

Just switched from MBP M1 Max, which had zero problems running this monitor in native 3840x1600, HiRes, 120Hz, 10bit 4:4:4 (with the help of BetterDisplay, no hdr), on MacOS Sequoia 15.5

For the life of me, I'm not able to replicate it on M4 - whichever combination of settings I select, enabling HiRes always kicks me back to 3360x1400. The flexible scaling is enabled.
Tried about everything in this thread that doesn't involve hardware change. Downgrading refresh rate, also with Shift key to show the fractional ones doesn't work.
In the M1 max, I could select 3816x1590 in macos settings, enable HiRes in BD, then up the resolution to native in BD.
On M4, I don't have the 3816x1590 at all, adding this in Custom Scaled resolutions doesn't enable it in native macos settings, selecting it in BD is either/or with HiRes just like the rest of resolutions higher than 3360x1400

Is there anything I can try or is it just not possible?

 

[Camel993]

All clear now. I downloaded it before the 9th of April, on the 8th actually, but now I'm over:

Firmware name: *BC_CM_MBP4k120
Firmware version: 7.02.116
Configuration file version: 0x040

Thanks for the heads up. VMMTool works just fine over parallels no need for the auto updater, but looks like it's worth to keep an eye on the firmware site.

Had to revert to the original firmware today. My secondary portrait screen had an ‘ant’ screen every time the Mac mini woke up from sleep or cold boot. I had to change the source constantly to get a proper display. It was annoying, not even a specific screen like the LG C3, just a simple gaming 144Hz 2K screen.


Downloaded the latest firmware updater and used it first.

Spyder_fw_USBC_CM_MBP4k120.fullrom, but that one was basically installed the same as mentioned above…thought that they might have updated

Then I tried the: Spyder_fw_USBC_CM_7.02.112_MacOS 4K120Hz only.fullrom
I think this one is one of the OG firmware versions I used to use at the beginning with my M1 MBP.

Anyway now I'm at:

Firmware name: *der_fw_USBC_CM
Firmware version: 7.02.112
Configuration file version: 0x040

Did not test it on my C3, as it's working just fine in the Mac minis with the built-in HDMI port.
Thought that I would share, maybe some are running into the same issues.

 

[Camel993]

Oh and BTW there is a macOS app to do firmware updates now, but it did not work for me (MacOS 15.5).

 

[cmChimera]

Oh and BTW there is a macOS app to do firmware updates now, but it did not work for me (MacOS 15.5).

My Mac says it cannot open it.