boards.txt did indeed have an issue.
I shortened the different entries by 2 chars (from NUCLEO_F303ZETX to NUCLEO_F303ZE)
Is there a limitation or is it bound to something else?
I have followed the wiki about adding a variant (created the linker script, system clock config, defined all the board pins, declared the variant in the boards.txt file)
I have then removed from the variant_NUCLEO_F303ZETX.cpp and variant_NUCLEO_F303ZETX.h all the pins ...
Is there anybody who already worked on that board? I am following the instructions how to add a specific board. For boards that are already supported, there are 2 cpp and 3 h files defined in the corresponding folders.
Questions: How do you go about generating these, for example variant ...