Dear all, I can confirm that Peter's tip above does work. Disabling the "above 4GB" option in BIOS-> Advanced->PCI Settings solved this problem and I was able to install Debian Stretch.
In my case, I used a USB stick as install medium and a USB-to-RJ45 converter for network installation (since the integrated network card is unsupported in kernel 4.9). Once finished, I installed the backport kernel (4.18 at this moment) and removed the USB-to-RJ45 converter. The computer is working perfectly. Thanks! Josep Guerrero
