juanito, this may have something to do with Libreboot and Xvesa not getting along. Some graphics-related applications (e.g., vbetool) work fine on my netbook (which has BIOS) but not on my T400 laptop (which has Libreboot).
I know that full-blown Xorg works fine on this laptop, though, as it I use the laptop daily with X in both Devuan and OpenBSD.
We could try using Xorg instead of Xvesa, but I know too little about graphics (and even less about graphics on TC) to change this without help.