cstrouse/lg-ultrafine-4k-and-5k-monitor-firmware.md

Last active May 6, 2026 22:36

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Firmware downloads and zip encryption passwords for LG Ultrafine 4k and 5k displays

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lg-ultrafine-4k-and-5k-monitor-firmware.md

https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/22MD4KA_MP7/FWLatestVersion.txt https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/27MD5KA_MP4/FWLatestVersion.txt https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/27MD5KL_TBT_PD/FWLatestVersion.txt https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/24MD4KL_TBT_PD/FWLatestVersion.txt

https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/22MD4KA_MP7/ https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/27MD5KA_MP4/ https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/27MD5KL_TBT_PD/ https://lmu.lge.com/ExternalService/lgscreenmanager/mac/FW/24MD4KL_TBT_PD/

The zip passwords were quickly found using the strings command. The password for each model consists of the model name followed by !LGahslxjqlalfqjsgh!@#:

22MD4KA!LGahslxjqlalfqjsgh!@#
24MD4KL!LGahslxjqlalfqjsgh!@#
27MD5KB!LGahslxjqlalfqjsgh!@#
27MD5KL!LGahslxjqlalfqjsgh!@#

jamesxsc commented Mar 5, 2026

I've recently bought a used LG 27MDKLA which I use with its original 2m active thunderbolt cable from a M4 Pro Macbook (Tahoe).

LG Screen Manager couldn't update the firmware (freezing at 20%), I've download the 3.10 version zip file from this topic, put it on the screen manager (without unzipping). Result is the same by freezing at 20%. I don't know if the 3.10 version is currently the latest or if I need to find the password of the file.

Could you help me the find the latest firmware and the solution to update? Thanks @jamesxsc @cstrouse

The issue is a bug double-freeing memory during programming of the scaler. I patched the app and ran successfully on my M3 Max running Tahoe: https://xscgroupltd368-my.sharepoint.com/:u:/g/personal/james_xsc_co_uk/IQDe5JyTr9N-QJFSNCQ2V3ucAcYAvsAWSKgPGnzgiVMuRi8?e=FTu38A

You may need to bypass security/ manually re-sign it to run it.

If that doesn't fix it, you'll want to look for crash reports e.g. ~/Library/Logs/DiagnosticReports/LG Screen Manager-2026-02-27-142637.ips

erkankenc commented Mar 5, 2026

I've recently bought a used LG 27MDKLA which I use with its original 2m active thunderbolt cable from a M4 Pro Macbook (Tahoe).
LG Screen Manager couldn't update the firmware (freezing at 20%), I've download the 3.10 version zip file from this topic, put it on the screen manager (without unzipping). Result is the same by freezing at 20%. I don't know if the 3.10 version is currently the latest or if I need to find the password of the file.
Could you help me the find the latest firmware and the solution to update? Thanks @jamesxsc @cstrouse

The issue is a bug double-freeing memory during programming of the scaler. I patched the app and ran successfully on my M3 Max running Tahoe: https://xscgroupltd368-my.sharepoint.com/:u:/g/personal/james_xsc_co_uk/IQDe5JyTr9N-QJFSNCQ2V3ucAcYAvsAWSKgPGnzgiVMuRi8?e=FTu38A

You may need to bypass security/ manually re-sign it to run it.

If that doesn't fix it, you'll want to look for crash reports e.g. ~/Library/Logs/DiagnosticReports/LG Screen Manager-2026-02-27-142637.ips

The app that you'd patched worked perfectly. At now, both version of apps show as "the software is currently up to date" (3.10,1.13,5237,3.05,0,1e for LG Ultrafine 27MD5KA). Thank you @jamesxsc

Currently on Tahoe 26.3:
All resolution, sleep/wake and USB functions work perfectly.
Only ALS Function isn't working as on the previous firmware. I don't know if this is a hardware or software issue, I suppose the disabled auto brightness function is common.