hi, you can add support for custom devices as described here: J-Link Device Support Kit - SEGGER Wiki Basically, you can create the folder structure in C:\Users\YOUR_USERNAME\AppData\Roaming\SEGGER\ There you create a new folder \JLinkDevices and then the subfolders for your Vendor and Device. In there you place your device.xml and the flm file (see screenshot below). Then you can adapt your device file according to your needs (below you see an example for STM32G491RC with a custom flash loader …