TG585v8 Woes

[#1]

Good  Morning Everyone
I've got something of a strange problem with the plusnet-supplied router. I originally tried support (some time back), but after checking that I hadn't done anything too stupid, they ran out of ideas. The problem never went away, but my thoughts only recently returned to trying to fix it.
Essentially, the problem is that devices connected wirelessly all have external connectivity: they can browse websites, SSH or whatever else they need to do. However, the devices have no internal connectivity: no windows/samba shared drives, no gaming, they can't even ping each-other. I originally wondered if the router was isolating clients for security reasons, but there doesn't seem to be a setting for this exposed in the TG585's web interface.
Normally, the router serves 3 clients: all windows XP: 1 desktop, 1 laptop and one media centre (cannibalised laptop). The same problem occurs with friends' laptops when they visit. If we fancy a LAN game of something we have to set up an ad-hoc network.
Originally, I wasn't sure whether it was something I'd done, or if it was the router. However, the smoking gun appeared when I (accidentally) power cycled the router: all was rosy for a few hours, before the situation returned to normal. I've power cycled once or twice since then, and the problem stays fixed for somewhere between half and four hours.
I've read this thread on stackoverflow http://superuser.com/questions/125052/cant-ping-other-machines-in-my-network and tried changing the WPA from mixed mode, disabling TKIP. This produced the same temporary fix as cycling. - The idea mentioned in that thread of setting static ARP mappings is something I'd rather avoid, falling squarely in the "nasty hack" bracket.
I also note another plusnet user has suffered a similar problem in http://community.plus.net/forum/index.php?;topic=94096.0 which was seemingly fixed with a firmware update. This seems like my next port of call, so in the first instance I suppose I'd like someone to point me towards the firmware and instructions to flash the misbehaving router.
I know I've given a lot of detail for a simple "where's the firmware?" question. I thought I'd be thorough in case anyone has come accross the problem previously and solved it without having to get their hands dirty.

[#2]

Instructions and links to the firmware you need are given in the Community Support Library article How to upgrade/download the firmware on the Thomson 585v7 and 585v8.
Hope this fixes things for you.

[#3]

Thanks sprayxt. - That's the info I hadn't been able to find.
I'll give it a whirl this evening, and report back with either my gratitude or sorrow.

[#4]

HI spheric
I can upgrade it for you remotely this afternoon if you wish? The router will be offline for about 10 minutes when I do it though.
Jojo

[#5]

Thanks Joanne, I nearly had to take you up on your offer!
The router did not want to upgrade. It failed 4 times over wifi, seeming to power down the wifi interface part-way through the update process, interrupting the transfer. It failed twice over cat5 (same thing) before finally working. I also struck unlucky in that it reverted to factory settings, too.
I'm pleased to say that it looks to have worked I'm mighty pleased to be seeing ping replies from the other computers... I've tested again this morning, and it still seems to be working. This is longer than any of the previous periods in which its seemed "fixed".
Thanks for your help: the problem wasn't a complete show-stopper, but It was an annoyance that I kept coming back to

[#6]

I had a feeling that would have fixed it. Glad to hear it though

[#7]

Quote from: spheric

I also struck unlucky in that it reverted to factory settings, too.

I'm pretty sure that the fimware update forces a reset, although it's a reset to Plusnet's original settings rather than factory settings.