Dr.HDMI 4K manual

What this box does

Dr.HDMI 4K sits between an HDMI source and everything downstream and decides what that source is told about the display. It stores forty EDIDs, presents one of them to the source, and fires a proper hot-plug event so the source reconfigures itself. Signal passes through at full 18Gbps with no added latency.

Everything else in this manual is detail on those two sentences.

In the box, and what you need

• Dr.HDMI 4K unit.
• Power supply, in your choice of EU, UK, US or AU/NZ plug.
• USB to mini USB cable — power, firmware updates and custom EDID upload.

You need nothing else for normal use. A Windows PC is only required if you want to write your own EDID into a custom bank or update the firmware.

Connecting it

HDMI in comes from the source: player, console, HTPC, set-top box. HDMI out goes towards the display, AV receiver, matrix or extender.

Where you place it matters. Put it directly after the device whose behaviour you want to change. If a player refuses to output HDR, the unit goes between the player and whatever follows. If a receiver mangles the EDID, the unit goes between the source and that receiver, not after it.

On a long run, place it at the source end so the input equalisation and the +5V injector work in your favour.

Connect the supplied USB adaptor to the mini USB port. With a supply attached the unit passes that power on downstream, which is what makes the +5V injection useful for active cables.

The five EDID tables

Forty banks are organised as five tables of eight. The LED colour tells you which table you are in, the number tells you which bank inside it. The printed labels on the unit list all forty.

• Blue — FHD. Printed on the bottom of the unit. 1080p, 1080i, 720p and 480p presets.
• Green — UHD full audio. Eight UHD video modes advertising every audio format including Atmos and DTS:X.
• Yellow — UHD 5.1 / SPDIF. The same video modes with audio capped at what an SPDIF return or older receiver carries.
• Red — UHD 2CH. The same video modes, stereo only.
• White — custom. Banks 1–7 are yours to program; bank 8 holds the EDID copied from the connected display.

Green, yellow and red carry identical video modes. Only the advertised audio differs. Start on green and step down only if the chain drops audio.

Selecting a table and a bank

1. Change table: hold the rotary switch down in any position. The unit cycles FHD → UHD 2CH → UHD 5.1 → UHD FS → Custom. The LED colour confirms where you landed.
2. Change bank: press the rotary switch up or down to step through the eight banks in the active table.
3. Wait one second. Stop moving and the unit activates the selected EDID and starts the hot-plug event.
4. Give it two seconds. The HPD event takes about two seconds, as the standard requires. The EDID is locked while it runs. After that you are free to change it again.

Some sources need a nudge afterwards — switching input away and back, or restarting the player. Windows machines sometimes need the display settings reopened.

Copying the EDID of your display

Short-press the copy sink button. The unit reads the EDID of whatever is connected downstream and stores it in custom bank 8 on the white table. A hot-plug event follows automatically and completes in about two seconds.

This is the starting point for most custom work: copy a display you trust, pull the file off with the Windows utility, edit what you need and write it back into one of banks 1–7.

HTPC mode and hot-plug reset

The second button carries two functions.

• Short press — HPD reset. Forces a fresh hot-plug event without changing the bank. Use it when a source is stuck.
• Long press — HTPC mode on/off. Hides the sink status from the source. Windows stops noticing that the TV switched off, keeps the resolution and leaves your desktop icons where they were.

The copy-sink button follows the same pattern: short press copies the sink EDID, long press performs a hard reset back to factory state.

Writing your own EDID banks

Custom banks 1 to 7 on the white table are user programmable. Bank 8 is reserved for the copied display EDID and is overwritten every time you press copy sink.

1. Install the Silabs USB driver for your Windows version from the downloads page. Windows 10 and 11 usually fetch it themselves.
2. Connect the unit to the PC with the supplied USB cable and start the Dr.HDMI 4K utility.
3. Load an EDID: read it from the unit, open a .bin file, or use one from the EDID collection.
4. Write it to a custom bank and confirm. Select that bank on the rotary control to activate it.

EDID files can be inspected and edited with third-party tools such as AW EDID Editor or MonInfo. Keep a copy of anything that works — a known-good .bin file saves an evening the next time you rebuild the rack.

Firmware updates

The unit is flashable over the same USB connection. Download the firmware package from the downloads page, connect the unit, and follow the updater. Factory presets on the blue, green, yellow and red tables change only through a firmware update; your custom banks are not the same thing.

RS232 and app control

The 3.5 mm jack on the output side is RS232. Integrators use it to switch banks from a control system without touching the unit, which is the point of putting one in a rack you can't reach.

The optional GoBlue Bluetooth and infrared dongle adds Android, iOS and IR control. It sits between the USB power source and the unit. The apps on Google Play and the App Store need it; without one, the rotary control, RS232 and the Windows utility are your three routes in.

When it doesn't work

• Still a black screen. Try a lower bank. Green 1 asks for the most; step down through 4K60 4:2:0, then 4K30, then the blue FHD table. If the picture returns lower down, the chain can't carry what you were asking for.
• Picture but no lossless audio. You are probably on a yellow or red bank. Move to green — same video, full audio.
• Audio drops out or stutters. The opposite: step down from green to yellow or red so the source stops offering what the chain can't carry.
• Nothing changes at all. Check the unit is in the chain in the right place: it only affects the device plugged into its input.
• Source ignores the new EDID. Short-press HPD reset, then power cycle the source. Some players only re-read the EDID on boot.
• Copy sink produced something odd. Displays behind a receiver often report a merged, reduced EDID. Copy directly from the display instead, or use a preset.
• Back to square one. Long-press copy sink for a hard reset to factory state.

Still stuck? The contact page explains where to send the details and what to include so you get a useful answer first time.