I'm pleased to inform all that, using Udoox86 Ultra, Debian amd_64 9.0.1 Stretch xfce4 non free firmware, K3b 2.0.3 set to 2x speed, PIONEER Slim Portable Blu-Ray Writer BDR-XD05TB connected to Digicom 4 ports USB 3.0 alimented HUB, I have successfully burned a data 100 GB Verbatim Blu Ray BDXL. This means that the hardware-software relationship is well-balanced.