Let me explain what I did first. I experimented last time with various FPGA/SYS/APP and I can’t remember what versions I mixed up, but after all I gave up.
When I tried your file today, it worked! It complained only about that licence code. Then I wanted to update FPGA/SYS/APP with latest versions for my HW2.81, but unfortunately it is now complaining about FPGA error on startup. So it works with some of the older FPGA/SYS/APP combinations, which I can’t remember 
so I still need to wait for SEEED stuff for their official release of DFU for HW2.81
Thank you wagnermerle anyway! Really appreciate.