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

Does this 4k@120hz tweak work for you?

  • Yes

    Votes: 195 78.6%

  • No

    Votes: 22 8.9%

  • Can not get the right Adapter

    Votes: 21 8.5%

  • Yes, but Apple limit HDR/HiDPI functionality with macOS 14.1 and macOS 15

    Votes: 10 4.0%
  • Total voters
    248
I have an LG C2, MBP 2 Pro (Sequoia Beta 15.5), and CableMatters 201388-A USB-C -> HDMI cable. Using the CableMatters update tool I end up with:
- Firmware *BC_CM_MBP4k120
- Version 7.02.116
- Config file 0x040

Directly flashing from Spyder_fw_USBC_CM_MBP4k120.fullrom via VMMHIDTool, I get the same result: 4k120 *without* HDR or HiDPI. I had HDR working before 14.0, which I think reflects the comments upthread about some HDR change by Apple.
 
Update: The 7.02.116 firmware seems to be a good improvement to the old .112 on my M1 Studio.

I have two LG C2s with 201388-A CableMatters adapters. I used to have to have BetterDisplay reinitialize the adapters ~3 seconds after turning the screens on, or one would occasionally show "No signal". On the newer firmware, I was able to remove that, now they just turn on instantly and correctly on their own.

No problems with HDR on either version, but IIRC BetterDisplay does something to help with those issues.
 
Worzel_ said:
I'm in the UK. I have a M2 MacBook Air & LG C4 42inch TV.

Should I be buying this CableMatters adapter: https://www.amazon.co.uk/dp/B0DCN798Y1

There are cheaper ones like this that also claim 4k@240hz: https://www.amazon.co.uk/BENFEI-Adapter-Aluminum-Braided-Compatible-Grey/dp/B0DLBDYF55/
Click to expand...
CM cables are one the only cables that can objectively and reliably push 4K at 240hz. Any other manufacturer has not been able to make this claim. Anker, UGREEN, the ones you linked. They all barely do 4K at 120hz (I sent 3 different Anker HDMI cables back as they had flicker issues on random occasions).

When it comes to Amazon, I'd avoid their recommendations and I wouldn't trust anything those random Chinese manufacturers say about their 32K@1800hz cables or whatever.
 
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ultratiem said:
CM cables are one the only cables that can objectively and reliably push 4K at 240hz. Any other manufacturer has not been able to make this claim. Anker, UGREEN, the ones you linked. They all barely do 4K at 120hz (I sent 3 different Anker HDMI cables back as they had flicker issues on random occasions).

When it comes to Amazon, I'd avoid their recommendations and I wouldn't trust anything those random Chinese manufacturers say about their 32K@1800hz cables or whatever.
Click to expand...

Ah thanks. Do you mean CM cables for the adapter only or the hdmi to hdmi cable too?
 
Last edited:
Can confirm because I messed up with the ugreen adapter. The type C to hdmi 2.1 adapter does implement A1 and the VMM7100 chip, but there seems to be a specific ugreen fw compatibility issue which has now rendered my adapter useless after flashing it without backing it up (I know....). Now it keeps going into some fallback mode upon connection and refuses to show anything on display. Does someone maybe have the original ugreen fw for this adapter to atleast get its functionality back? (Resetting VMM7100 with betterdisplay also didn't work)
 
  • Wow
Reactions: ultratiem
just get my new setup working at 4k 120hz hdr (and 4k 144hz sdr):
m1 and m4 macbook air, both on macos 15.4
cable matters 201392
kensington sd5700t
tcl qm851g 65"
 
I used the newest firmware from CM released in March 2025 LINK , and it works well so far. Has anyone else had any experience with it? Mac models M4 must use the newer firmware version. Iam on M1 MAX with an CM USB-C>HDMI Adapter VMM7100, i will report if issues like standby problems are resolved (Update: for me the standby issue is solved with this new firmware)

The release notes are:

- The new firmware resolves the issue of DPtool not working under macOS.
- After restarting the computer, the resolution for 4K120Hz RGB will be downgraded to 4K120Hz 420.

Info: Don't forget to set your HDMI input on your TV or monitor back to PC mode!

The new Firmware:
Bildschirmfoto 2025-04-29 um 14.22.32.png


The new Firmwareversion is 7.02.116

IMG_9076.jpeg
 
Last edited:
joevt said:
I think I lost track somewhere. What does "DPtool not working under macOS" mean? Isn't "VmmDPTool64.exe" a Windows app?
Click to expand...
I'm not sure what they mean by "DPtool not working under macOS." They probably mean VM Parallels Desktop on macOS — some have reported that it no longer works with certain adapters.
 
I bought the Cable Matters adapter.
www.amazon.com

Cable Matters 48Gbps USB C to HDMI 2.1 Adapter with 100W Charging, 4K 240Hz /8K 60Hz HDR - Thunderbolt 4 Compatible with iPhone 16/15 Pro Max (Max Resolution on Any MacBook is 4K@60Hz)

Cable Matters 48Gbps USB C to HDMI Adapter Supporting 4K 120Hz and 8K 60Hz (DSC required) HDR, 100W PD - Thunderbolt 3 and Thunderbolt 4 Port Compatible - Maximum Resolution on Any MacBook is 4K@60Hz
www.amazon.com

I ungraded the firmware, and the adapter just broken, it doesn't recognize as an adapter anymore, please help!
 
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I just got my adapter today from the Spanish Amazon and it's the 201488 version.

While I'm able to switch the heartz to 120Hz out of the box without a problem I'm now facing an issue with the resolution since Mac's top bar doesn't show up within the screen limits when my LG C2 is set to a resolution of 3840 x 2160.

What am I doing wrong?

Thanks
 
Oceveth said:
I just got my adapter today from the Spanish Amazon and it's the 201488 version.

While I'm able to switch the heartz to 120Hz out of the box without a problem I'm now facing an issue with the resolution since Mac's top bar doesn't show up within the screen limits when my LG C2 is set to a resolution of 3840 x 2160.

What am I doing wrong?
Click to expand...
The top bar is called a menu bar.

There's some kind of overscan option on the TV that you need to disable? Maybe select a PC mode? or a 1:1 mode? Check the manual.
 
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Reactions: Oceveth
joevt said:
The top bar is called a menu bar.

There's some kind of overscan option on the TV that you need to disable? Maybe select a PC mode? or a 1:1 mode? Check the manual.
Click to expand...
Thanks it was not set for PC mode and I forgot it automatically changes when i remove the HDMI. Solved!
 
my M1 Max works well with LG C3 42 4k@120hz with the cable matters hub.
The only issue I have is when I put Macbook into sleep, LG C3 won't turn off, it keeps showing screening saver.
Is it possible to put the monitor into sleep and wake up follow the Macbook like a normal monitor?
 
twilightgod said:
my M1 Max works well with LG C3 42 4k@120hz with the cable matters hub.
The only issue I have is when I put Macbook into sleep, LG C3 won't turn off, it keeps showing screening saver.
Is it possible to put the monitor into sleep and wake up follow the Macbook like a normal monitor?
Click to expand...
U have to enable standby in macOS settings when plugged in.
 
twilightgod said:
my M1 Max works well with LG C3 42 4k@120hz with the cable matters hub.
The only issue I have is when I put Macbook into sleep, LG C3 won't turn off, it keeps showing screening saver.
Is it possible to put the monitor into sleep and wake up follow the Macbook like a normal monitor?
Click to expand...
It’s not a monitor, it’s a TV. I know people think they are the same, but they are actually really different. TV’s don’t have the same communication capabilities that monitors have. Namely things like DDC that provide your OS with extended features and controls. Brightness, sleep, etc. TV’s are quite dumb in that they basically accept signal and then do their own post processing.

The C-line of LG’s has its own set of quirks you have to work around. Hammerspoon provides some automation but it will always be quirky as it relies on networking loopbacks which complicate matters. Reliability plummets unfortunately.

I have disabled the screen saver on the TV which replaces the bright ass images that will actually diminish the lifespan of the panel for a black screen and some text. The setting is on the TV. The timer is set to 15m and not adjustable (thanks LG). I have set no screen saver on macOS and set the screen to shutoff after 10m. This means I get the LG black screen for 15m after 10m of inactivity and then the TV will go into hibernation. So I lose the nice macOS screensavers. But this also means I don’t need to run Hammerspoon, I don’t need to give the TV network access (only for updates). You’ll find out sooner or later but you can’t make this a true computer display. You’ll always need to fiddle with the TV to some degree.
 
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 !!!!
 
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