No picture, dropouts, HDR that never engages or audio stuck in stereo all get called a handshake problem, yet the causes differ. A cable may be at its limit. The source may be reading an EDID you did not expect. An AVR may pass on a trimmed-down capability list. Or the display input needs an enhanced or high-bandwidth HDMI setting switched on first.
A five-step diagnostic routine
Step 1 — Check both ends of the link
Look at the default OLED info page or the MAIN section of the web server. RX reads connected when a source is present, TX reads connected when a sink is present, and SIGNAL shows active once video flows. With an FRL signal, the OLED shows the FRL rate and the web server lists the lanes and Gbps per lane.
If TX never reads connected, check the output cable and TX +5V FORCE in CONFIG. It is on by default; switched off, the display is not detected, as if the cable were unplugged.
Step 2 — See what the display really advertises
Open EDID TX in the web server, or turn the rotary switch to the TX EDID page on the OLED. You get the sink’s EDID name, its maximum video format and its audio support. Compare this with EDID RX, which is what the source reads at this moment.
Step 3 — Drop to a simpler, known table
Switch to CUSTOM EDID and pick a predefined table below your target, for example a 4K60 4:2:0 8-bit 300MHz table instead of 4K120. If the picture now locks reliably, the fault lies in the extra bandwidth or features the original EDID offered.
Step 4 — Reintroduce features one by one
Return to COPY TX SINK EDID and MODIFY. Begin conservatively, with the FRL rate capped or disabled and VRR, HDR and Dolby Vision removed. Then enable one item per test and note which change brings the fault back.
Step 5 — Force a fresh handshake
HPD events follow an EDID change automatically. To trigger one by hand, click ISSUE HOTPLUG in CONFIG for a soft reset of the setup. If the source keeps its old format, restart it.
Reading the results correctly
A reduced EDID that works where the original failed does not prove the display is defective. It shows that a certain mix of bandwidth, color depth, chroma, HDR, VRR or audio formats is where negotiation breaks down. Cable, input settings and firmware still need checking.
Also rule out HTPC mode in CONFIG. It helps Windows PCs when a display is switched off, but it is not compatible with HDCP signals, so keep it off for protected content.
Bandwidth depends on the cable
For a 1500MHz / 48Gbps link, the manual calls for a certified or tested 48Gbps HDMI cable in copper or fiber. The unit amplifies and recovers the signal as a repeater, but no EDID setting makes an undersized cable carry that signal reliably.
Questions about handshake troubleshooting
Will the DR HDMI 8K solve every HDMI fault?
No. It helps you find and manage EDID and handshake issues, but it cannot make a cable, source or display handle a signal beyond its physical limits.
How do I make the source renegotiate without unplugging cables?
Use ISSUE HOTPLUG in the CONFIG section of the web server. Some sources also need a restart after an EDID change.
Where can I check whether the source and display are detected?
The default OLED info page shows RX and TX status, and the MAIN section of the web server reports RX and TX as connected.
Want a test point in your chain?
The DR HDMI 8K is available from HDFury.eu.