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@stevemr123 Ya! I got it to work, thanks for your tutorial.
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@PatricioooAG @esfrost I have a strong suspicion the issue is with your USB-C to HDMI adapter.

I recently bought this adapter from Cable Matters https://www.amazon.com/dp/B08MSWMXT4
I applied a firmware to it from here: https://kb.cablematters.com/index.php?View=entry&EntryID=147

I learned about this adapter and the firmware resolution from a Reddit thread where PC guys were also trying to get 4K120 from iGPUs:
Did u have 4k 120 hz RGB 4:4:4 ? can u show me this
 
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Works great @stevemr123!
I updated the firmware on the cable matters adapter and I now have 4K120 on my LG C2 with my M1 MaxMBP. I'm going to try it with my M1 MBA next. I was just about ready to click buy on the M2max MBP 16 to get 4K120, but now I got around Apple's fake limitation I'm happy enough to not upgrade at this time. I'm only getting 4:2:0 and not 4:4:4 though. Has anyone been able to get the better chroma?

PS found a fly in the ointment. I can't get HDMI audio to work through the USBC Cablematters to HDMI adapter after modding the EDID. Anyone else with the same issue?
 
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@stevemr123 Thanks for your great work! For a long time I have been troubled by mac can not output 4k120, and I dont want to upgrade to m2 pro/max as there is barely performance gain.
 
This seems promising, but I wasn't able to get it to work from the built-in HDMI port on Mac mini M1 to an LG CX. All resolutions and refresh rates are the same as before, sadly.
 
@stevemr123 Thanks! With a modified EDID (as in your guide) I am now getting 4K@120Hz (non-HDR, have not tried HDR) without subsampling (The menu says YCBCR444 8b 4L8) on a M1 Pro MBP 14 connected to an LG C1 48" via a cheap RSHTECH hub. The hub uses a VMM6100 that I updated with the firmware from Cable Matters (lol).
 
I have just ordered the Cable Matters usb-c to hdmi 2.1 adapter on Amazon. Will get back to you guys once I got it and test it.
 
This seems promising, but I wasn't able to get it to work from the built-in HDMI port on Mac mini M1 to an LG CX. All resolutions and refresh rates are the same as before, sadly.
Yeah, the built-in HDMI port is HDMI 2.0 so it is guaranteed not to work. You'll need a compatible HDMI 2.1 dongle, hub or converter cable. It seems like the results are mixed even with some HDMI 2.1 adapters.
 
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Tried the custom EDID for my C2 (even tried the one provided here)
Unitek V1414A does not work. They have newer model V1416B with DSC and VRR tho. *but not available in EU retail

I may wait a tad to see which active adapter yields the best results.

mbp m1 max 14
 
Tried the custom EDID for my C2 (even tried the one provided here)
Unitek V1414A does not work. They have newer model V1416B with DSC and VRR tho. *but not available in EU retail

I may wait a tad to see which active adapter yields the best results.

mbp m1 max 14

That's great because I just ordered an Unitek V1414A lol. 🤣
 
Anyone had any luck on M1 Mac Mini yet? I also wonder if this override can go around the 48khz audio lock on HDMI on apple silicon
 
4k 120hz Chroma 4:4:4 does also not work with my USB 4 Station. Also RGB 4k 120hz does not work. Only 4:2:2 does work.


Whe have to test the Docks/Adapters to see if one will work.
I ordered 2 new Adapters and 1 new TB 4 Dock with HDMI 2.1 for testing if there's a limitation in not using TB 4!
 
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Works great @stevemr123!
I updated the firmware on the cable matters adapter and I now have 4K120 on my LG C2 with my M1 MaxMBP. I'm going to try it with my M1 MBA next. I was just about ready to click buy on the M2max MBP 16 to get 4K120, but now I got around Apple's fake limitation I'm happy enough to not upgrade at this time. I'm only getting 4:2:0 and not 4:4:4 though. Has anyone been able to get the better chroma?

PS found a fly in the ointment. I can't get HDMI audio to work through the USBC Cablematters to HDMI adapter after modding the EDID. Anyone else with the same issue?
How did you update the firmware on your adapter? Was it with macOS or do you have a PC?

I have a PC but when I plug it in it won’t let me update it. It gives some error message.
My build has a 5800X3D so there’s no integrated graphics so I can’t plug in a display as the instructions state.
 
How did you update the firmware on your adapter? Was it with macOS or do you have a PC?

I have a PC but when I plug it in it won’t let me update it. It gives some error message.
My build has a 5800X3D so there’s no integrated graphics so I can’t plug in a display as the instructions state.
I had to use my Lenovo Legion 7 to update mine as you're right, unless you have a way to actually have the adapter functioning and carrying a video signal, you won't be able to update it. I guess I could've tried using my 2019 i9 MBP 16 to update it too, but I didn't have it with me.
 
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I have just ordered the Cable Matters usb-c to hdmi 2.1 adapter on Amazon. Will get back to you guys once I got it and test it.
It should work after firmware update. It's the one I got. You will need a Windows computer or likely an Intel MacBook running bootcamp with video capable USB C ports to update the firmware. I also had to have the adapter functioning by having it plugged into my TV in order to flash it.
 
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Works great @stevemr123!
I updated the firmware on the cable matters adapter and I now have 4K120 on my LG C2 with my M1 MaxMBP. I'm going to try it with my M1 MBA next. I was just about ready to click buy on the M2max MBP 16 to get 4K120, but now I got around Apple's fake limitation I'm happy enough to not upgrade at this time. I'm only getting 4:2:0 and not 4:4:4 though. Has anyone been able to get the better chroma?

PS found a fly in the ointment. I can't get HDMI audio to work through the USBC Cablematters to HDMI adapter after modding the EDID. Anyone else with the same issue?
You update cable matters with a Mac ? I dont have only Parallels. Thanks.
 
I had to use my Lenovo Legion 7 to update mine as you're right, unless you have a way to actually have the adapter functioning and carrying a video signal, you won't be able to update it. I guess I could've tried using my 2019 i9 MBP 16 to update it too, but I didn't have it with me.
Thanks. I’m running a 2018 Mac Mini so I supposed I could temporarily install windows on it again. (Had to do that to build the Windows 10 USB install drive for my PC build)
 
The Cable Matters firmware update tool is Windows-only (.exe file).

However, I'm not 100% sure the adapter will need the firmware fix for Macs. For sure it helps with Intel iGPUs and LG OLEDs.
It didn't work me until I did the firmware flash, but I could've done something else wrong.
 
I have the Cable Matters, and without the update it does not work on my MBP M1 MAX. I don't have an available PC or intel Mac to flash it.
 
I have the Cable Matters, and without the update it does not work on my MBP M1 MAX. I don't have an available PC or intel Mac to flash it.
Sorry to hear you're having troubles with the update. But you've confirmed that it does need the update in order to work. If you can borrow a Windows PC, the update is relatively quick and painless.
 
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