OSX automatically overwriting bootsector?

[Cliffton Beach]

I've been triple booting OSX, Debian Linux and Windows succesfully for nearly a year. I use Lilo as my bootloader (prefer it to Grub), installed to the MBR. Recently I upgraded to 10.4.10 including kernel (uname -a returns Darwin jc-dentons-computer.local 8.10.1 Darwin Kernel Version 8.10.1: Wed May 23 16:33:00 PDT 2007; Sochi2014:VoteForUs/RELEASE_I386 i386 i386).

 

This worked for a while. Yesterday I booted into OSX and stayed there for longer than usual to test out some Java code in OSX, then shut down. This morning when I powered back on, there was no Lilo. I got a message about can't find com.apple.Boot.plist. ?? Where had Lilo gone? It seems like OSX overwrote the bootsector, and OSX was set to start (though i failed).

 

One linux liveCD later and Lilo is restored. OSX works just fine selecting it in Lilo (am there now) but what happened to Lilo in the first place? Does OSX try to automatically "fix" the bootsector? Why hasn't it happened before? Does it happen after a certain amount of time, or at a certain time of day? All I did aside from messing with Java (had success) is check for software updates (there were none).

 

Curious to know if it's happened to anyone else, or if anyone has any ideas why it happened. No big deal and easily fixed, but a PITA if it's going to be a regular occurence. I'll post back if it happens again of course.