How to update gt p1000 system 2.2 in 2016?
As long as SamMobile and XDA-Developers still exist, you will not toss that thing into the recycling bin without a try.

Start from updating the thing to official Gingerbread firmware available for download from SM (download page also offers tools and a brief guide), then install custom recovery and flash whatever you want from there. If you don't mind the lag you could even install CM13 (Android 6.0.x) for some fun.