I used to run Linux (JLime Linux) and NetBSD on those. I did prefer the bigger NEC MobilePro competitors though, but I spent so much time on those Jornadas in college.
Kristoffer Ericson was the driving force behind JLime Linux.
Along with OpenZaurus, these early hobbyist efforts to run Linux on embedded devices formed the basis of what became OpenEmbedded and has since been renamed Yocto, still one of the most commonly used embedded Linux development platforms.