iphone model a1203

I bought IPHONE 5 and used itunes to transfer the contacts from Iphone model a1203 (8GB). I thought to update to a new software for model a1203 as a way to remove the old contents and restore it as new to give to my son.

After running the update sofware iphone 3gs as the latest update for the telphone. When It was over, I got insert sim card, though it has already in, an image with connection cable and itune music icon, in addition to IMEI: 01 130100 240759 0 ICCID: unknown when I press (i).

I

know it is a software error, as the phone was working nicely. Now using itunes, it does not allow me to access the iphone again to re-install. what shall I do?

I guess it is apple responsibility to give right advice on what to do if it is a compatibility issue and we are Apple loyal.

please give a step by step on how to restore the telphone to it old backup if the new software is not compatible.

best regards

ibrahim