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What to do when the device isn’t detected

The ZDMA doesn’t show up in Device Manager on your Debug PC? The guide below asks about what you can actually see, then tells you exactly what to fix. No technical background needed — most people finish in about two minutes. If you would rather work through it yourself, skip to the full reference.

Full reference

The guide above follows whatever you actually see. If you would rather check things yourself, or want to understand what each step is ruling out, everything is below.

1. Reading the LEDs on the card

The ZDMA has two Thunderbolt ports and one JTAG port. There are two kinds of LED and they are not in the same place, so don’t mix them up:

• Amber LED — at a fixed position on the card; shows whether the ZDMA itself is working
• Green LEDs — one beside each Thunderbolt port; shows the link state of that port

Check amber first, then green — while amber is wrong, there is no point looking at ports or drivers.

2. Confirming the port really is Thunderbolt / USB4

The ZDMA can only be reached through a genuine Thunderbolt or USB4 port. An ordinary USB-C port looks identical but has none of the PCIe tunnelling the ZDMA needs — plug into one and no driver will ever make it work. That is not a fault, it is the wrong port.

• The reliable check: see what controller Windows reports. Press Win, open PowerShell, paste the line below and press Enter (read-only, changes nothing) — if devices with Thunderbolt or USB4 in the name appear, the machine has one.
• You must also confirm which port: the machine having a Thunderbolt port is not the same as the cable being in it. Usually only one or two Type-C ports qualify; on a desktop the front-panel ones generally do not, and laptops often support one side only. Don’t go through a dock or hub — connect directly.
• The easiest way to tell: try the cable in each Type-C port in turn — the one that makes the card’s green LED go solid is the right port. No manual needed.
• Full method: four ways to check, how to find which port, a markings table and the common traps are in Is my port Thunderbolt or USB4?

Get-PnpDevice | Where-Object { $_.FriendlyName -match 'Thunderbolt|USB4|Host Router' } | Select-Object Status,Class,FriendlyName | Format-Table -AutoSize

3. The Thunderbolt driver (the most common cause)

Most “green LED on but not detected” cases are this one. The link is up and Windows can feel the device arrive — it simply lacks the driver needed to talk to it.

1. Open the support page of whoever made your computer or motherboard and find the download page for your exact model (not a generic driver).
2. Download the Thunderbolt / USB4 driver and Thunderbolt Control Center — you need both.
3. Install them on the Debug PC — not the machine the card is installed in.
4. Restart the computer, then reconnect the Thunderbolt cable and test again.

Not sure which download is right? Use the AI helper below and it will give you the exact link and install order for your machine.

4. The Thunderbolt switch in the BIOS

Plenty of boards ship with Thunderbolt disabled, or with the security level set to require authorisation. Without Control Center installed the approval prompt never appears, so the device is silently blocked — which looks exactly like it not being detected at all.

1. Shut down. Press Del or F2 repeatedly while starting up to enter the BIOS (the key varies by brand; the boot screen usually says).
2. Under Advanced, find Thunderbolt Support or USB4 and set it to Enabled.
3. Set Security Level to No Security.
4. Save and exit, then reconnect and test after the restart.

5. Firmware (only relevant if you have flashed it)

The ZDMA ships with firmware installed and works out of the box. If you have never opened Vivado or used a flashing tool, skip this section.

But if you flashed firmware and the trouble started afterwards, a wrong or unfinished flash is very likely — and it looks exactly like a bad cable or missing driver, so no amount of driver work will help. Put the firmware back to the default and test again:

• Use the flashing tool to restore the default firmware (recommended): just follow the firmware flashing guide. The tool fetches the default firmware for you, so there is no file to find and nothing to match to your chip.
• Just want the file itself? Normally you don’t need it — the tool has already retrieved it. If you really are flashing by hand, the FPGA0 default firmware is available here (file name pcileech_zdma_100t_fpga0.bin; it works on every ZDMA — the 100t in the name does not mean it is only for the 100T).

6. Connection method and power

• Order of connection: connect the cable first, then power on. Plug both ends of the Thunderbolt cable in before switching the computer on — that is the most reliable order. Plugging in after it has booted often ends in a failed negotiation and nothing detected.
• Direct connection only: no dock, hub or adapter in between — the ZDMA plugs straight into the computer’s Thunderbolt port.
• On a laptop: set the power mode to High Performance and plug in the mains adapter. In power-saving modes the Thunderbolt controller may be throttled or switched off.
• Cable: the one supplied with the card is a genuine Thunderbolt cable and is usually fine to use; but its compatibility is not always perfect and on some machines it will not carry the device. To rule the cable out completely, buy an active Thunderbolt cable (with a chip in the connector) — compatibility is noticeably better. Ordinary USB-C and charging cables frequently carry no data at all — never use those.

7. Let AI read your PC (no need to know your model)

Several of the steps above depend on the specifics of your board — whether it has Thunderbolt, where the BIOS option lives, which driver to install. You don’t have to look any of that up yourself: generate a “system report” on the computer, send it to an AI, and let it answer from your real hardware. That is far more accurate than quoting a model number from memory.

Step 1 · Generate the system report

Press Win, type PowerShell, open it, then paste the whole block below and press Enter. A file called zdma-report.txt appears on your desktop and opens in Notepad — that is the report.

$o = "$env:USERPROFILE\Desktop\zdma-report.txt"
"=== System ===" | Out-File $o
Get-CimInstance Win32_ComputerSystem | Select Manufacturer,Model | Out-File $o -Append
Get-CimInstance Win32_BaseBoard | Select Manufacturer,Product | Out-File $o -Append
(Get-CimInstance Win32_OperatingSystem).Caption | Out-File $o -Append
"`n=== Thunderbolt / USB4 ===" | Out-File $o -Append
Get-PnpDevice | ? { $_.FriendlyName -match 'Thunderbolt|USB4|JHL|Ridge' } | Select Status,Class,FriendlyName | Format-Table -Auto | Out-File $o -Append
"`n=== Devices with a problem ===" | Out-File $o -Append
Get-PnpDevice | ? { $_.Present -and $_.Status -ne 'OK' } | Select Status,Class,FriendlyName | Format-Table -Auto | Out-File $o -Append
"`n=== Recent PnP / WHEA errors ===" | Out-File $o -Append
Get-WinEvent -FilterHashtable @{ LogName='System'; ProviderName='Microsoft-Windows-Kernel-PnP','Microsoft-Windows-WHEA-Logger' } -MaxEvents 15 -EA SilentlyContinue | Select TimeCreated,Id,Message | Format-List | Out-File $o -Append
notepad $o

Step 2 · Send the report to an AI

Open the report in Notepad, select all and copy, then send it together with the prompt below to an AI — ChatGPT, Claude or Doubao all work. The prompt already describes your situation and the four things to ask; you only need to paste the report at the end.

I have a ZDMA card (a Thunderbolt/USB4 DMA device) installed in one PC and connected by a Thunderbolt cable to the PC I operate, but Windows on the PC I operate won't detect it. Below is a system report from that PC. In plain language, tell me:
1. Does this machine really have Thunderbolt/USB4, and which port should I use?
2. The exact BIOS menu path for THIS motherboard to enable Thunderbolt Support and set Security Level to No Security.
3. The exact Thunderbolt/USB4 driver + Control Center download for THIS model, and the install order.
4. What the Kernel-PnP / WHEA errors in the report mean.
Ask me only for what's missing.

--- SYSTEM REPORT ---
[paste the report here]

You can run PowerShell commands on my Windows PC. This is the PC I operate. A ZDMA card (a Thunderbolt/USB4 DMA device) is installed in a separate PC and connected to this one by a Thunderbolt cable, but Windows on this PC won't detect it (nothing in Device Manager, though the green LED on the device is on).

Don't ask me for hardware details - find them yourself. Run commands to collect: motherboard and system model, Windows version, any Thunderbolt/USB4 controllers and their driver status, any present devices whose status isn't OK, and recent Kernel-PnP and WHEA-Logger errors from the System event log.

Then tell me, in plain language:
1. Whether this machine has real Thunderbolt/USB4 and which port to use.
2. The exact BIOS steps for this motherboard to enable Thunderbolt Support and set Security Level to No Security.
3. The exact driver and Thunderbolt Control Center download for this model, and the install order.
Keep every step simple and wait for my confirmation before changing any setting.

8. Still stuck? Have these ready when you open a ticket

If the common causes are all ruled out and it is still not detected, it needs a person to look at it. Send all of the following at once so we can help on the first reply instead of asking back and forth:

• Your check history from the guide — finish the guide and press “Copy for support”; that carries everything in one go
• The exact model of the motherboard or laptop (for example ASUS ProArt X870E)
• A Device Manager screenshot taken with the cable connected
• A screenshot of the Thunderbolt / Security Level page in the BIOS
• LED state: whether amber and green are solid / blinking / off, and which port you used
• The SID printed on the card’s label
• Firmware history: flashed, or still as shipped

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