My 1st post, great board.

So T-Mobile UK don'thave 4.1OS available for the 7290, but I did download the Vodafone version, removed the vendor.xml file, connected to 7290 and it worked somewhat, no e-mail available.

Did a device reset which left the 4.1 software on, rang t-mobile UK, they sent message settings and it's all working perfectly now (in prep for using the Parrot CK3100 B/tooth car kit (phonebook wouldn't transfer on OS <4.1).

Hope this helps.

That is the way it is supposed to work. Firmware releases for the same device model are interchangeable between the different carriers. As you mentioned, the only thing you need to do is to delete the vendor.xml.