Cable Matters48Gbps Unidirectional USB C to HDMI 2.1 Cable - 6ft, Support 4K 240Hz and 8K 60Hz HDR - Thunderbolt 3, Thunderbolt 4, USB4 Compatible with iPhone 16/15, Max 4K@60Hz on Any MacBook

I have an ASUS laptop featuring Thunderbolt 4 with one having DisplayPort alt mode. Bought a Dell WD22TB4 dock to use with it to have a one cable solution for my laptop docking. The dock could not output 4K@60hz on its HDMI port as it should have per the listed standards compliance. I didn’t really think it would, since the product documentation didn’t explicitly say so and it has three DisplayPorts as well. Therefore I bought two of these cables, one for my wife’s laptop and one for mine — we have the same laptop. It worked on hers, but the dock’s TB4 port labeled for DisplayPort would cause the monitor to be recognized as a Synaptics device @1080p every time the display would sleep. I moved the cable to one of the dock’s other TB4 ports and it works perfectly now. As of the time of this review, updating the dock’s firmware and gfx drivers didn’t change the issue. Fault of the dock, not the cable. Still a good dock and would recommend it vs other TB4 docks. Then I had an issue on my laptop as well. There was a BIOS/UEFI update recently for our laptops, that I noticed had reduced my previous USB-C dock’s speed (noticeable by Ethernet speeds). I didn’t try to investigate past this observance at the time, though it was one motivator for me to get a TB4 dock and this cable sooner rather than later. I watched update and noticed it also included TB4 controller firmware. With the Dell dock attached and updated, DisplayPort alt mode did not work at all. I thought ok, I’ll move it to the other TB4 port and use DisplayLink until I could troubleshoot further. The other port didn’t work at all. I tried connecting this cable directly to my TB4 DP alt mode port and got nothing. I swapped cables between my wife’s machine and mine, and the cable was fine. That’s when it occurred to me. A lot of the peripheral controllers on a motherboard don’t ever lose power, especially in the case of a laptop that never reaches 0% battery level. If some issue occurred initializing the TB4 controller after the update, the only way to re-initialize it, would be to pull the battery. Of course my laptop has an internal battery that, thankfully, isn’t too much of a pain to get to. I unplugged the battery cable, held the power button down for a minute, put it back together, and everything works perfectly now.The point of my story… if this cable doesn’t seem to be working as described, it’s probably not the cable. It could be, but it’s less likely than some connectivity issue or bus limitation.

This cable did not work for my use case out of the box. However, I saw another reviewer mention a custom firmware! After googling "cablematters 201362 m1 pro firmware" I was taken to a guide on the Cable Matters website with a custom firmware which has appeared to work for me. I did not have a Windows machine with USB-C that could do DP Alt Mode, but I was able to leverage Parallels to get the job done. Be sure to download "VmmHIDTool" from the Microsoft Store, as the "VmmDPTool 64" that came from Cable Matters would not work for me. After following their instructions with the tool from MS Store to flash the cable with the custom firmware I simply unplugged the cable and plugged it back in and was able to select 240hz refresh rate on my monitor! Hopefully this review helps others cut to the chase. Once I had everything I needed, the flashing of the firmware could not have been simpler.Will update this review if the cable begins to exhibit any issues, but so far the custom firmware appears to have solved the issues on my MacBook Pro with M1 Pro chip!

I've been holding out for properly working HDMI 2.1 receivers for a while now. I've actually bought and returned 3 Denon and 1 Marantz receiver. They all claimed the HDMI 2.1 functions were fixed but they weren't. I'm currently testing a pioneer receiver but they are all the same company so I'm not holding out hope.So in the meantime I'm using this to split audio to my HDMI 2.0 receiver because eArc is... terrible, at least it is using my 3080ti FTW3 Ultra. No audio, audio from the wrong channels, audio in the wrong format...sigh.I had been using a 2080ti FTW3 Ultra on the same receiver but now I need 4k120 HDR VRR, ALLM etc etc lol.So I needed to think outside the box. I wanted ALL the audio formats my PC can output and receiver can decode and that means no eArc. So how do you take USB C and make it work?Easy! This adapter and a free program called Virtual Audio cable. Basically I have video coming out of my GPU & going to my LG C1. Then I use virtual audio cable to send any audio formats out through USB C, into this converter then I just plug the HDMI cable into my receiver and I have a solution to a ridiculous problem that should never have existed to begin with.I can adjust everything you can think of using virtual audio cable so when you use it with a converter like this is the best possible solution for our current HDMI 2.1 audio woes.

We bought this cable to use in our car to easily display phone content on the screen for the kids (other parents will attest to the importance of in-car entertainment on long trips). It's been working very well, but recently stopped transferring data. Despite troubleshooting with other devices and various ports (my husband works in IT), the cable isn't even detected anymore. Considering the fact that I bought it in April this year and it stopped working in July, that seems like an extremely short lifespan for an almost $40 cable (and of course it's now outside the return/exchange window). I did try messaging the seller through their website messenger, and no response after a week. Here's hoping I can get an exchange or refund.