That's what I inferred from the replies I got on this topic and the merchant's saying. Although I do blame him for not "finishing up" the work, he has been honest so far, as the phone started to act up right in front of him, losing then recovering signal incessantly. From what I read, there has been two productions of the 3GS, but ways to tell are not quite clear. On the good side: if I get to understand what problems are commonly encountered while unlocking an iPhone, maybe I will be able to do it myself later.
I read that this "grafted" 06.15 baseband was also reported to drain the battery faster than usual, in addition of instabilities. So I expect a much lower consumption after downgrading.
As I encountered no great success trying to communicate and place an order for an IMEI unlock, I was also liiking for a way to do it myself, but still don't know where to connect, how to request authorizations, if it requires some kind of license, etc.
Independant question still unanswered: do an iPhone 3GS needs the original carrier's SIM to be able to unlock it, or any SIM will do, even if the phone is not activated?
What carrier is your iphone locked to?
If its AT&T the IMEI are really cheap. Like $2-3 or so. All you need to do is send the seller your payment along with the phones imei number and within 24hours will be unlocked.
And yes the ipad bb had many sideeffects like faster battery drain etc...
If you JB and unlock it using ultrasnow you wont need the original carrier sim. You can hactivate using redsnow or snowbreeze.