An issue has been identified affecting HDR calibration on certain LG displays running firmware version 33.10.30 and newer. After a 3D LUT is generated and loaded into the display, the LUT may not become active immediately, resulting in calibration results that do not reflect the newly created LUT.
At this time, this issue appears to affect HDR calibration modes only. SDR calibration is not believed to be impacted.
LG has acknowledged this behavior and is currently working on a firmware update to address it.
Symptoms
You may be experiencing this issue if:
- Measurement results or visual evaluation indicate the calibration has not been applied.
- Verification measurements produce results similar to pre-calibration values.
Cause
A software issue introduced in LG TV firmware version 33.10.30 and newer may prevent the display from properly activating the uploaded 3D LUT, even though the upload process completes without error.
Workarounds
Until a permanent fix is available, the following methods may help activate the LUT:
Method 1: Reboot the TV
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- Power the TV off.
- Turn the TV back on.
- Recheck measurements.
This may activate the LUT, but the result may not always persist.
Method 2: Toggle Signal Type
-
- Change the pattern generator output from HDR to SDR.
- Switch back to HDR.
- Recheck measurements.
This may activate the LUT, but the result may not always persist.
Method 3 (Most Reliable): Re-run the 3D LUT Calibration
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- Perform the 3D LUT calibration a second time.
- Verify results after the second pass.
Running the calibration again has been observed to most consistently produce a persistent LUT.
Status
LG is actively working on a firmware update to resolve this issue. This article will be updated as more information becomes available.