This post is a continuation of the thread "Ci20 freezes randomly when wifi interface is left on", where this forum will not allow me to reply more than three times to one thread, because it's bloody stupid.
I believe I have in fact significantly improved the behaviour of the board, with regard to freezing.
It turns out the four-port Syncwire USB charger I was using to power my dev board collection is not in fact 2.4 amp on each port - two ports are 2.4 amp, and two are 1.0 amp. I believe the Ci20 was on one of the 1.0 amp sockets.
It is now on one of the 2.4 amp sockets, and last night it ran for 11 hours and built GCC 4.5.4.
(This was with wifi on, just BTW).
As an aside, before I realised this, I actually saw a kernel panic in the board when it was idling;
Message from syslogd@ci20 at Apr 10 22:37:31 ...
kernel:[14756.747900] Fatal exception: panic in 5 seconds
Message from syslogd@ci20 at Apr 10 22:37:35 ...
kernel:[14761.754707] Kernel panic - not syncing: Fatal exception
Timeout, server ci20 not responding.
Which isn't of much use, but hey, thought I'd post it : - )