There is; as I suggested, search on singtel; there's a 2-page thread discussing it, with a link to something on singtel's site about it, IIRC.

I also saw a nice writeup online of how to customize a firmware image for, e.g. corporate deployment. I don't recall anything about locking users out of upgrades, but if the Windows updater is cautious enough, it should be possible to trip it up like this.

Thanks to this (timely) post, Singtel may now become the rallying cry of the anti-HSPA crowd. OTOH, it's evidently straightforward (with current tools, and pre-Fremantle distributions) to debrand, so it's to be hoped the same will be true for the N9xx (if it gets branded firmware at all.)