I would say the BT technology is a f... joke by itself. I cannot understand how they screwed up such a simple thing so much. In A2DP, why use some ugly codec instead of directly filestream mp3 to the headphones for them to decode it? Instead, they wire BT chip to the analog output of the device, and use very lossy SBC low complexity codec. Ogh, yeah, they saved 1$ per licence to mp3 tech owners owners... and arguably increased battery life. That's very important, since every new phone receives a worse battery - forts 1500mah, then 1200, now they are around 1000mah. Dumb again, since the processor clock is increased, and they already have a 1500mah developed.

Well, you thought wrong. Recently, SIMPLE SECURE PAIRING v 2.1 was introduced. I dunno why on earth is there any need to simplify dumb enough procedure of "see digits on one device screen, enter them on another". Anyway, the code is now noneditable.
In my case, the PC gives one code, N900 gives another, and there's no freaking way to change it.
See the picture.