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Trouble with TB4 KVM - downstream hub's non TB ports have no data

  • r

    Hi,

    I recently purchased a TB4 KVM from Microcenter (pretty sure I got the last one!). It works great as a KVM, but I've noticed that I can't use USB-A or non TB USB-C ports on hubs that are connected downstream via TB4. I've tried swapping all cables in the chain with new ones, and this happens whether I am using a Caldigit TS4 downstream or the hub capabilities of the Dell U4025QW monitor. What can I do to resolve this? Should I be considering a warranty replacement? Is that even possible at the moment given curent availability?

     

    Some additional notes/thoughts:

    • Right now the chain is Macbook Pro (M4 Max) -> SB-TB4K -> Caldigit TS4/Dell monitor. I do have another TB4 hub I'd like to put between the laptop and KVM but I've taken that out of the chain for now while I troubleshoot. I also eventually plan to have both the monitor and the TS4 hub connected downstream if I can get this resolved, but I've only kept the monitor connected for now to keep the simplest setup while I try to narrow down the source of the problem.
    • On the TS4, I have confirmed that the unusable ports are at least powered because I can use them to charge things, so I guess it's just data connectivity that's a problem? On the Dell monitor, the ports appear to be unpowered.
    • The non TB4 ports start working again when the hub/monitor is connected directly to my laptop which is why I believe the KVM is causing this behavior.
    • From this thread I have gathered that older devices had some issues. My serial number is 47786080302XXX which is scarily close to 47786080301794, the serial number where the fix was applied according to the thread, but it IS above that number.
    • The TB4 ports on the downstream hub(s) will accept non TB4 supported devices and they work as expected with my laptop.
    • I've attached the Macbook's System Information report for Thunderbolt/USB4 in case that helps. I can provide vanilla USB as well, it's just longer. I've tried to remove identifying information but if any of that is necessary to help with troubleshooting, let me know and I can either add them to this thread or send you them separately.

    Thanks!

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  • S

    @raman325 Hey, I've reported this to the team. We're going to check in on this. The serial looks good and it's possible a firmware update will fix it, in which case you can get one from customer service/technical support. If it's a hardware issue or defect specifically to that unit, then it may require replacement.

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  • r

    @Sabrent much appreciated! Let mek now if there are any other details I can provide to help the investigation.

    Regarding a replacement, is that something I would do through you or Microcenter? If it's Microcenter, what happens if they don't have stock? Thanks again!

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  • S

    @raman325 Different vendors have different return policies. If it's possible to go through the retailer, that should be the first option. If not, it would be part of the process in engaging our customer support team. Your serial does look good, we in fact handfixed some models even within the early range as well, but that was unrelated to any Mac issues. For that we put out a firmware fix. That should apply to all retail models but you could check with the team.

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