How to Make some Arduino SRAM memory locations write protected?

I really want to edit the arduino bootloader (Optiboot) to read initial (Power On) SRAM random values for finding any pattern they are following.

well, you could look at this thread on avrfreaks: http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=141279
(Isn't that you? I thought we had well-covered the idea that you don't need to modify optiboot to be able to look at the initial RAM values.)