From orange to O2
you could try this
By doing the reset (1st temp) you will lose all your
data ie contacts, messages, photos, videos etc etc so
back them up on your pc first.
Take out your sim card and follow the instructions below :
1st temp. put this number in the keypad
*2767*3855# let it reboot(restart)
now its ready for permanent.
Put in a sim card of a network that the phone won't
except and follow the instructions below.
( If you can't type anything with a locked sim
card inserted just take it out and do the next
step without a sim card in the phone)
Don't worry if your screen shows - - - - - - - when typing
it is supposed to do this.
AND THEN *#7465625# to check the locks....all locks are
inactive...these are all the locks...
network lock - inactive
subset lock - inactive
sp lock - inactive
cp lock - inactive
sim lock - inactive
activa lock - inactive
phone lock - inactive
auto network - inactive
auto subset lock - inactive
auto sp lock - inactive
auto cp lock - inactive
auto sim lock - inactive
This procedure does not change your imei number at all