2005 120d Aux Port

[13aines]

Hi All,

My friend just bought a 55 plate 120d which had a flat battery for months. It has an aux port under the arm rest, but I cannot for the life of me change the source to aux.

I read something online that said after a flat battery, the optional extra needs coding back in by BMW, but this seems nuts?!

I have flashed ECUs before with TuneECU, and I have used VAGCOM before. Is this something I could do myself, if I could acquire the right software?

Thanks in advance,

Matt