OpenZaurus
Openpsion (formerly psilinux) is a project to port the Linux operating system to a group of palmtops produced by Psion. At present, working linux systems can be installed on any of the Series 5, Series 5MX, Series 5MX-Pro, Revo (Revo+, Mako) machines (NOT the Series 3).
All root file systems are based on either Debian or handhelds.org (openembedded) linux, since precompiled binary packages (e.g., “*.deb” or “*.ipk” files) for the ARM processors are available. The Debian approach (Sarge) is presently the most developed. Installation of linux on a Psion requires some prior experience with the linux operating system.
Download link to the distribution ISO