Off-topic: mobile phone firmware upgrade

[John Warner]

Dear all,

Apologies for writing in English.

I have a Nokia 6230i which I synchronise with my ubuntu laptop. I am
aware that it does not have the latest firmware on it and still has the
mobile company in the UK who sold it to me Logo etc on it.

How do I upgrade the firmware debrand it preferably under Linux but I
have access to a Windows machine?

I suspect I might have to go to a shop and have it done - any
recommendations?

In friendship

John Warner
in Bielefeld.