I've recently been doing something similar: I have a UbiSurfer 9, a netbook using an S3C2416 chip as its CPU, running the ARMv5 instruction set, and with 128MB of DDR2 memory. Its original operating system is WinCE 6.0, and I'm trying to run Linux on it. The good news is that Debian still maintains the armel architecture, so we potentially have a large number of userspace programs available. The bad news is there's no suitable kernel and bootloader. Fortunately, a friend helped me write a bootloader and modified the kernel source code to make it work. Running a Debian system is possible, but quite slow, so I created a minimal system with only Busybox[1], and it works perfectly.
[1]: https://github.com/chirsz-ever/busybox-linux
I'm still exploring this; related information is in this repository, written in Chinese:
Risc PCs were obscure machines, even then and compared to the original Archimedes (which itself was an oddity), so lacking support isn't surprising. A 710 model not upgraded to a StrongArm would have come from well outside the enthusiast sphere which is where all the dev work was happening. (So probably a school model from a time when schools were heavily moving to PCs).
Back in 1995/6 or so it seemed like half the Acorn employees at Acorn World had their Risc PCs running NetBSD. By 1995 if you were doing software dev on Risc OS your environment and tools were absolutely terrible compared to what existed on Mac/PC/Unix, which was a factor that contributed to people interested in programming abandoning Acorn hardware entirely.
I think the saddest part is that it can’t run Acorn’s Unix. It had IXI’s desktop tools, which were really nice back then when time itself was new.
Run RISC OS and contribute!
A lot of the problems encountered here seem to be due to bit rot, unavailable archives and these were, from my experience, not too uncommon for relatively rare Linux platforms like the RISC PC even more than 20 years ago.
RISC PC systems are still a supported (tier 2) platform in NetBSD. You should be able to cross-compile the whole system including X11 from any Linux or NetBSD host (I did this last week for the next68k port) and the developers would certainly be happy about feedback before the 11.0 release is published. So this might be worth giving a try.
https://wiki.netbsd.org/ports/acorn32/
https://www.netbsd.org/docs/guide/en/chap-build.html
Not everything is working in NetBSD all the time. When testing the “previous” NeXT emulator, we faced some nasty regressions last year that prevented NetBSD 10 (and, as we found out, every release after 5.2.3!) to run on next68k, but things were fixed eventually thanks to the nice and friendly next 68k platform maintainer!