I've a vodafone one s (vodafone italy but I presume that all vodafone-branded one s are equal) and it works with all operators, I'm using it with H3G italy and it works perfectly. If you want to fully debrand the one s you must wait for s-off to change CID. However if you don't like vodafone spam you can find some nandroid backup of the stock no-brand rom in this forum, but with those can't install future ota updates
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