I installed firmware version 4.2.7 (from
http://www.speedtouch.co.uk/510.asp) on my ST510 using the Mac install
program. It installed the firmware, but before restoring the
configuration it reported that it had failed. From the lights on the
box it appeared to running, but failing to connect to ADSL (which is
what you'd expect if it had lost its configuration).
I couldn't connect to it from any of my machines; they're on the
10.x.y.z network (with x != 0) and the ST510 had been using its
default address of 10.0.0.138.
After much experimentation it turned out that I could connect if I
changed my computer's IP address to 10.0.0.something: the router was
using a netmask of 255.255.255.0 as if it were on a class C network.
I ran the "easy setup" wizard from the web page and told it to use
255.0.0.0 and all was well, except that I'd lost my configuration (the
file format seems to have changed).
So if you're thinking of installing 4.2.7,
(a) don't
(b) if you do, make sure you do it from a machine with a 10.0.0.something
address.
-- Richard