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

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!@#

Tried the patched version. Update button still fails at 20%. I've downloaded the firmware from the link above, but I can't figure out what file to open with the updates? I tried the zip file itself, and tried looking in each unzipped folder, and there's nothing the updater is happy to work with.

I needed to reboot after installing the patched version. I suspect because of the lghub_updater background process that auto-spawns itself even if you force-quit (which I think was keeping the broken version running in the background even after installing the patched version, until I restarted). Got the firmware updated, and this fixed my wake issues with an LG 27MD5KL. Thank you!

27MD5KL-B and Tahoe 26.5.1. I tried the update using the patched app above, and it was able to get past the 20% hang I was experiencing with the stock LG Screen Manager app, so thank you!

But, when I try to update using the patched app, it reaches about 85% then stops the upgrade and shows the following:

I've tried unplugging the monitor from power and USB, waiting 5min, upgrading again - same issue. Anything else I can do?

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

27MD5KL-B and Tahoe 26.5.1.
I successfully updated to the laste version using this patched version!

Really appreciate it! 🚀 ❤️ 🙇

Thanks for your patched app, @jamesxsc! I have two 27MD5KA (one at home and one at work, so they're never connected at the same time). I've successfully managed to upgrade the firmware to 3.10 for one of the two. But trying it for the second one failed at 20%. It crashes at 20% when using the official app. And it aborts at 20% using the patched app, bringing the same popup mentioned above "Please unplug the cable...".

I've checked the log at the path you've mentioned, but only the official app had written one ("likely double-free").

Also, I've used the same M3 (Tahoe 26.5.2) while attempting to upgrade both of them.

Any idea? Thanks!

@jamesxsc thanks a lot for the patched LG Screen App. The one from App Store kept loading fw till 80% and failing. With your patched app I updated my 27MD5KL-B to the latest firmware. I am running it with Tahoe 26.5.2 on M1 MBP connected via Amazon basics thunderbolt 4 cable. Versioning is really crazy on those firmwares, but it looks like I got fw ver 3.14

Dear users, could you please help me and provide the firmware file for the 27GR93U-B.AEU monitor (27GR93U - BB.AEUDMTN)?
I want to install it manually by selecting the file from the list of files to be installed via the app, rather than online through the app.
Thank you in advance for any help.

Thanks for your patched app, @jamesxsc! I have two 27MD5KA (one at home and one at work, so they're never connected at the same time). I've successfully managed to upgrade the firmware to 3.10 for one of the two. But trying it for the second one failed at 20%. It crashes at 20% when using the official app. And it aborts at 20% using the patched app, bringing the same popup mentioned above "Please unplug the cable...".

I've checked the log at the path you've mentioned, but only the official app had written one ("likely double-free").

Also, I've used the same M3 (Tahoe 26.5.2) while attempting to upgrade both of them.

Any idea? Thanks!

Weird: one week later I've tried it again and it suddenly worked, out of no apparent reason.

Hi, Do you have the complete firmware dump? The 1MB one to flash into the EEPROM?

Hey @jamesxsc, thanks so much for the patched app — really appreciate the work you've put into this!

I'm hitting a snag on my 27MD5KL (Mac Mini M4, Tahoe): the update consistently stalls at 40% and prompts me to unplug/reconnect the cable. I've tried the original LG Thunderbolt cable, connecting directly with no hubs, a different Thunderbolt port, a full overnight power cycle, and even dropping to a lower resolution before starting — same result every time. With patched app I successfully updated 22MD4KA.

Any ideas would be hugely appreciated — happy to share more logs or details if that helps track it down!

So I am not a SW engineer and admittedly asked AI to support with this, btw issue seems the following according do Sonnet:

Update on my 27MD5KL issue (stuck at 40%, unplug/reconnect prompt): I checked the crash logs and found something more specific than a generic failure.

The crash isn't in LG Screen Manager itself — it's in the bundled helper tool `dfu-util_mac_apple_silicon` (at Contents/Resources/dfu-util_mac_apple_silicon). It crashes immediately on every single launch with EXC_BREAKPOINT (SIGTRAP) inside `_libsecinit_appsandbox`, before any of its own code runs:

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libsystem_secinit.dylib _libsecinit_appsandbox.cold.6 + 60
1 libsystem_secinit.dylib _libsecinit_appsandbox + 1968
2 libsystem_trace.dylib _os_activity_initiate_impl + 64
3 libsystem_secinit.dylib _libsecinit_initializer + 196
4 libSystem.B.dylib libSystem_initializer + 280

Code signing team ID on the crashing binary is 5SKT5H4CPQ (LG's own), so this is the original unmodified dfu-util binary, not something altered by the patch.

I tried clearing the app's sandbox container (~/Library/Containers/<bundle-id>/Data) in case it was a corrupted container — same exact crash afterward, byte-for-byte identical stack trace. That rules out a stale container and points more toward a missing/incompatible sandbox entitlement on this specific helper binary (possibly needs `com.apple.security.inherit` to properly inherit the sandbox from the parent app).

Running macOS 27.0 (26A428) on a Mac mini M4 (Mac16,10). Given this crashes on every invocation regardless of cable/port/retries, I suspect this is what's actually causing the 40% stall on my end — the app hits the point where it needs to shell out to dfu-util to flash the monitor, and that process dies instantly every time.

Happy to share the full crash report if useful for debugging.

Follow-up to my earlier post — found the root cause and a working fix for my 27MD5KL stuck at 40%.

Root cause: entitlement mismatch between LG Screen Manager and its bundled helper tool.

• The main app binary (Contents/MacOS/LG Screen Manager) has no entitlements at all — it's not sandboxed.
• The helper Contents/Resources/dfu-util_mac_apple_silicon declares com.apple.security.app-sandbox AND com.apple.security.inherit. The inherit entitlement only works if the parent process is itself sandboxed and hands off its sandbox context to the child. Since the parent isn't sandboxed, the helper crashes immediately on every launch trying to inherit a sandbox that doesn't exist — always at _libsecinit_appsandbox.cold.6 (EXC_BREAKPOINT/SIGTRAP), before any of its own code runs.

This matches exactly what several of us have been seeing: the update stalls partway through (my case: 40%) with the "unplug/reconnect cable" prompt, because the app is trying to shell out to dfu-util to actually flash the monitor, and that helper dies instantly every time — regardless of cable, port, retries, etc.

Fix that worked for me:

sudo codesign -f -s - "/Applications/LG Screen Manager.app/Contents/Resources/dfu-util_mac_apple_silicon"

This re-signs the helper ad-hoc, stripping the app-sandbox/inherit entitlements so it no longer tries to inherit a nonexistent sandbox. Verify with:

codesign -d --entitlements :- "/Applications/LG Screen Manager.app/Contents/Resources/dfu-util_mac_apple_silicon"

(should return no entitlements plist afterward). Relaunch LG Screen Manager and retry the update.

Note: this modifies the app bundle's overall seal, so Gatekeeper may complain the app is "damaged" on next launch — if so, run sudo xattr -cr "/Applications/LG Screen Manager.app" and try again.

Setup: 27MD5KL, Mac mini M4, macOS 27.0 (26A428). This was blocking me even with the patched app, since the patch addresses a different bug (the double-free in the main app) and doesn't touch this helper's signature.

@jamesxsc — might be worth stripping these entitlements from dfu-util in the patched build too, could fix this for others hitting the same wall.

The garbage LG Screen Manager app from the app store crashed at 80% and my LG 27MD5KL monitor turned teal, and it's still teal after using the patched application that successfully updated it. I suspect it's because it's the lack of the red channel, found someone with this similar issue here.

Photo/screenshot

Any ideas?

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

Thank you for your help.