WB55 FUS upgrade fails, keep getting "security extension not instantiated" error message
I'm trying to flash the FUS and BLE_stack to the co-processor, but the CubeProgrammer drops me the error below. I could not even delete the previous FUS as the release note said. Same error message. The flash was erased by changing the protection byte to 0xBB and then back to 0xAA. Could that be my problem? The MCU is on a custom PCB, and the important parts are the same as on the WB55-Nucleo and I'm using a nucleo with s-link to program through SWD. The application runs perfectly on the M4 (except the bluetooth part).
So the error message is: "Error: Could not execute fwupgrade command, Security extension not instantiated".
Any help is appreciated.
Thanks in advance!

