Question about ipod classic/video hardware (not a Rockbox specific question)

[Frankenpod]

This isn't really anything to do with rockbox, but hoping someone might be familiar enough with the hardware to know the answer.

Having flash modded and rockboxed a lot of ipod classics, and found the process to vary hugely in how easily it proceeds (many times it 'just works' without having to do anything much beyond a simple restore and RB installation, while other times it takes hours of struggling and repeated attempts), I was wondering about one specific ipod hardware question - do the ipod classics put all the firmware stuff (and, also, rockbox's bootloader) on a (hidden?) part of the internal storage (whether original hard-drive or flash replacement), or is there an additional bit of flash memory on the logic board where it puts that stuff?  Was wondering if some of the problems that arise could be because the latter is the case and that sometimes that bit of extra storage misbehaves?

I know sometimes a failed restore will end up showing two partitions on the ipod, one tiny one and one with 99% of the storage space.  What's going on there?