Jump to content

Latitude 7400: Troubleshooting Thunderbolt3


Recommended Posts

You don't need legacy boot option. Just add modGRUBShell.efi (in the download link) as an EUFI tool to OC\Tools\ folder, then add it to config.plist:  misc->Tools. At the OC picker screen, hit-space bar to show all Auxiliary tools (if they didn't show up), select modGRUBShell.efi to launch it. Enter the commands (my post above) to modify the settings. Recommend #1, and #2 (64MB should be OK, as Herve pointed). #3 may be optional. Once done, reboot.

WARNING: Make sure you enter the exact commands above!!!  If you modified the wrong cells, it could brick the BIOS!


Update: With DVMT Pre-Allocate set to 64MB, you can remove the following keys from the Device Properties for iGPU (no patching of the VRAM is necessary):



Link to comment
Share on other sites

@Hervé you are absolutelly right. May be my memory misleaded me with Legacy Boot when setting up the DVMT on other hack long time ago.

Soo the problem with the grubshell was something messed up with the plist. I redo everything manually and finally was able to set the right parameters. [email protected] is working without any problems now. Thank you so much @Hervé and @BillDH2k! I added some properties in DP to fix the finnicky HDMI hot/cold plug and now it's working well for both. Here's a screenshot of my DP with the properties I found to be the best for the moment.





  • Like 1
Link to comment
Share on other sites

@Baio77  I've tried your TB3 patch on my 5400 which happens to have the Thunderbolt option, and it worked perfectly. During the testing, I've found that my TB3 device (Dell TB16 docker) has a flaky connection, likely due to the wear of the connector pins, which made intermittent contact and causing similar problem I've encountered with the 7400. If a good connection is made, the 5400 worked perfectly on the TB3 port, either cold or hot plug. So I believe the 7400 would be working fine if I had a good cable.


  • Like 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...