There are significant changes in:

/vsh/module/savedata_auto_dialog.prx [related to auto-loaded savedata]
/vsh/module/savedata_utility.prx [related to savedata in general]
/kd/power.prx (for some reason, 0x1F31 went from 0xFD in 5.02 to 0xFC in 5.03)
/kd/lflash_fatfmt.prx (for some reason, 0xC98 went from 0x32 in 5.02 to 0x33 in 5.03)

Apart from the standard changes (index.dat, pspbtcnf.bin, loadexec.prx) literally every other change was just an update of the internal version number from 5.02 to 5.03

I can confidently say that this update does ABSOLUTELY NOTHING but patch the GripShift exploit.

 They've specifically added a check for the American, European, Japanese, and Korean versions of the game. It will automatically detect the savedata as corrupt, and refuse to display it on the list of available saves.