from where do you know that its correct phone? just some of them can be reprogrammed, not all, so...
"Ultrascan obtained Nokia 1100 phones made in Bochum, Germany. Phones made around 2003 in that now-closed factory have the firmware version that can be hacked, Becker said. Nokia has sold more than 200 million of the 1100 and its successors, although it's unknown how many devices have the particular sought-after firmware."
"That application allows a hacker to decrypt the Nokia 1100's firmware, Becker said. Then, the firmware can be modified and information such as the IMEI (International Mobile Equipment Identity) number can be changed as well as the IMSI (International Mobile Subscriber Identity) number, which allows a phone to register itself with an operator.
The modified firmware is then uploaded to the Nokia 1100. Certain models of the 1100 used erasable ROM, which allows data to be read and written to the chip, Becker said. For the final step, the hacker must also clone a SIM (Subscriber Identity Module) card, which Becker said is technically trivial."
I don't really think that u have correct one, otherwise it worth xx.xxx$