[Sony Xperia P, U, Sola, Go] jonmorris:
The only plausible reason I can imagine for this being the case (which is certainly unique) is that the operators put Sony under a lot of pressure to deliver ICS.

Think about it, they were retailing a phone since March and probably advertising to customers (and over the phone via customer support) that it would get ICS in Q2. As a result, Sony - which must have limited manpower for rolling out ICS worldwide - had no choice but to prioritise the branded versions ahead of the generic versions.

Also, given our heavy subsidies in the UK, I doubt there are that many SIM-free sales compared to some other markets. While it's usually far cheaper and convenient to buy SIM-free, then have the freedom to change network with monthly-SIM contracts, or even PAYG, to get the best tariffs at any given time, most of 'Joe Public' are still thinking 'free phone' and happily signing up for £35, £40, £50 even £70 a month contracts - which is quite outrageous, especially if over 24 months.

I even wonder if there was pressure from Google to roll out the ICS update, as they recently published on their blog about ICS now reaching almost 11% of devices. Given how many Sony models are now with ICS, once the updates are done I can see there being quite a big swing. Again - to do this quickly, you probably do the network branded models ahead of SIM-free models.

Just look on the bright side; those with generic phones are going to be able to swap to the next Sony model at the end of the year (or early 2013) a lot quicker and easier than those hooked into long contracts!

---------- Post added at 12:11 PM ---------- Previous post was at 12:00 PM ----------

Having two Xperia S phones, the main problems I had with a UK generic phone flashed with the Swiss ROM were on the model that I did a complete wipe on.

In the other ICS thread, there are many people insisting on you doing a complete wipe. Some have implied the phone will be virtually unusable if you don't.

In my experience of actually doing things both ways, the model that got the wipe has had new problems.

1) When roaming internally (i.e. T-Mobile to Orange and vice versa), I now get the R symbol to show roaming. On the model upgraded, it will only show R for INTERNATIONAL roaming.

2) I lost the use of Wi-Fi channels 12 and 13.

On the model that was upgraded, I presume not doing the wipe kept some configuration files intact. When I rebooted with ICS, the phone went through and updated all the apps (over 300 of them!) and once allowing the phone to do some more updates, and apps like Gmail to cache mail back to 30 days etc (while doing so, the phone appeared more sluggish than normal), I've had relatively few problems at all. Wi-Fi seems to drop out more often than normal (suggesting the phone measures signal strength/quality differently) but that's about it.

As I said in the other thread. In the first instance, do a backup of your phone. Then do the upgrade (if you're going down the flashtools route) without wiping data. Let the phone do the upgrade, just as it would if you'd updated via SEUS.

Then give the phone a few days and see what it's like. Only then, if it's a real dog, should you do a full wipe and start over.

I wish someone would make this advice a sticky somewhere, as everytime I read someone saying to wipe everything, forcing a whole evening wasted restoring apps and data, and possibly having issues with localised features (Wi-Fi, roaming and stuff I may not have even noticed yet), I want to scream!!