Hi everyone,
I post this so maybe you don't get caught on the same problem I had.
If you don't connect to the EPFL VPN, the quartus compiler is creating a *_time_limited.sof file instead of the regular file, and doesn't change the regular one. So when modifying the code on eclipse, you then get a ELF error because the bsp doesn't correspond to the code uploaded to the FPGA.
So, don't forget the VPN!
Good luck to everyone