HDMI KVM Switcher Hotkey Support

I am using a KVM switcher to connect the laptop provided by the company and my personal laptop.
The KVM switcher I’m using supports hotkeys, and the method is as follows.


The current UHK Firmware version I’m using is 8.10.12. The reason is that in versions beyond that, the KVM switcher’s hotkey doesn’t work properly. By watching the attached video link, you can see that the hotkey functions properly in the 8.10.12 version. I’m curious if it works well in the latest firmware version. It didn’t function properly in the 9.x version, and I had a terrible experience disassembling the keyboard for a hard reset. I don’t quite understand the reason they didn’t include an external hard reset button. Anyway, I’m curious if the hotkey for the KVM switcher works properly in the latest firmware.

If I am not mistaken, NKRO is the thing that breaks KVM switches. The option to disable NKRO has not been implemented yet (see Firmware 9.0.0 breaks KVM's hotkey sequence. · Issue #536 · UltimateHackingKeyboard/firmware · GitHub ), so no, it still does not work.

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Does that mean I should never upgrade the firmware to 9.x.x.x, if I want to continue using the KVM switcher?

You should wait with upgrade until the linked issue is resolved, and then use uhk with the newly implemented 6kro settings.

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Hi Jae-Yong_Chung, I’m the original reporter of this issue. According to the hotkey used in your video, I believe there is high chance that we are using the same KVM.

I have a custom build firmware that is based on version 10.0.0 (and agent 3.x), it removed NKRO support to make it compatible with my KVM.

In my case, my KVM hotkey works in this custom-built firmware, and everything works fine for me (as I don’t need NKRO).

If you want to try if it works with your KVM, you could download it from Release uhk-firmware-10.0.0-kvm.tar.gz · brianhsu/firmware · GitHub

Of course, use it at your own risk.

Also, please connect your keyboard to your computer directly when doing firmware update. In my experience, it usually will brick the keyboard if updating firmware when the keyboard is connected to the KVM.


You are my lifesaver. After updating with the firmware you sent, I confirmed that it’s working well without any issues, and I couldn’t help but shout with joy. I can’t understand why UHK hasn’t addressed this issue for several years since it was raised. It’s strange that they keep saying there is no keyboard supporting the KVM Switcher. I hope that UHK will definitely take your provided firmware into consideration, and that the issue with KVM Switcher support will be resolved in the next firmware version. Anyway, thank you so much~!

Thank you very much for the custom firmware build, @brianhsu!

@Jae-Yong_Chung I’m sorry this issue hasn’t been addressed yet. I can clearly see this is an issue for some users, and we’ll implement a solution (6KRO option and USB interface reordering), but it’ll come with a larger, sweeping firmware change.

Hello, mlac.
I was informed there is new firmware through UHK Agent software.
The New Firmware has no problem with this issue?

I believe there was no change in respect to this issue, which means that it probably still has the issue.

I want to press the firmware update button, but I’m hesitant because I’m worried something might go wrong. If a problem occurs, I’ll have to open the keyboard case, perform a hard reset, and then frimware downgrade again. This process is very cumbersome and tedious.

USB interface reordering was implemented in firmware 11.0.0, which, for some, can resolve KVM-related issues. But, likely, the 6KRO option should also be implemented to resolve most KVM-related issues, which has not been implemented yet.

Got it. So, this means it’s better to delay the firmware upgrade for now because it isn’t fully supported yet, right?

In the meantime, using Brian’s 6KRO firmware build is recommended.