Info on bootloaders =)

[piranime]

Does anyone has some info on bootloaders and why they can`t be modified like i remember some famous bootloaders like in the wii, cellphones and how do they work to protect the main parts of the other components.

Hope someone can give me some hints or recomended readings to be able to understand how is this done.

Thanks in advance =)

[kAy]

Hope you find your answer here

http://www.cs.tau.ac.il/lin-club/lin-club_files/linux-boot/slide0000.htm