Hi,
So a couple of weeks ago i went to the US and bought an iPhone 4. It has 4.0.2 out of the box and was activated with official at&t SIM card.
As of now, I am in my country and waiting for the 4.1 JB and subsequently plan on updating to 4.1 (retaining baseband 1.59.00) to JB (in case 4.0.2 isn't supported by greenpoison) and unlock with Ultrasnow.
My problem is that when i restore to 4.1 I will lose my activation (not sure whether greenpoison will hacktivate). In order to be prepared for anything I was looking into buying one of those Universal iPhone Activation Sim cards from eBay. I emailed them asking weather their activation sim works on 4.1, but the (Chinese) seller confused me by answering:
"By the way, pls ensure that your phone serial no match your the imei no. . if two no don't match, it cann't be activated. If s/n no. is 83936WMN3NP, which also cann't be activated."
Can anyone deduce what he means? Are Serial Numbers and IMEI supposed to be the same? Because mine aren't.
Thanks for your help. Any comments on my approach to hopefully JB/Unlock my iPhone 4 are also welcome. Thanks!

Originally Posted by totono8

but the (Chinese) seller confused me by answering:
"By the way, pls ensure that your phone serial no match your the imei no. . if two no don't match, it cann't be activated. If s/n no. is 83936WMN3NP, which also cann't be activated."
Can anyone deduce what he means? Are Serial Numbers and IMEI supposed to be the same? Because mine aren't.

His comment makes zero sense.. These two numbers are not supposed to be the same.

Doesn't mean the product he is selling won't work, just means he has no clue. I would try and find another seller that seems to have a clue - unless it is so cheap (and the buyer feedback is good) that it is worth taking the risk

You should be able to use Phonebook SIM or MagicSIM 6-in-1 or 16-in-one 2010 version at least on a 3GS. I'm not 100% certain on iphone4.
However, there is one catch. If you activate using those SIM, it will activate but .... when you swap SIM, it will bounce back to the activation screen on the phone. This is because lockdownd need to be patched.
With that said, currently there is no patch available for IOS 4.1 for the 3GS and iPhone4 therefore you will encounter the scenario I mentioned above.