[dundee] dd revisited

[Nistur]

Ok, I still haven't got quite to the bottom of this dd thing, and now I 
have a new problem. I installed OSX to a friend's laptop, when we tried 
getting audio to work and rebooted, the thing froze on the apple logo. 
We reinstalled and I said I'd make a backup to her external storage, 
forgetting that it would be FAT32 and her partition size is 10GB.
Basically, I've looked into using search and count to create 2GB chunks 
which then (hopefully) I could put back together if her system goes bust 
again.
I got confused though. I managed to get the first one with:
dd count=4194304 if=/dev/sda3 of=/mnt/usb/OSXBackup.1
When I tried:
dd search=4194305 count=4194304 if=/dev/sda3 of=/mnt/usb/OSXBackup.2
it started off the filesize as 2GB. I didn't check to see whether FAT32 
would make later volumes, that would start at 4GB for example. I just 
thought I should check before I make a mistake. My main concern is that 
I overwrite the first part of the next partition when I dd it back when 
the inevitable happens and appleazalia messes up again. I also don't 
know how easy it would be to tar everything up as I haven't yet found a 
liveCD that can access a hfs partition :(

Thanks in advance and I'll continue googling
Nistur