Re: [Ipodlinux-devel] iPodLinux loader v0.1 (was: Re: new ipod, etc)

[Bernard L. <le...@bo...>]

Hi Dani,

On Tue, 2003-11-11 at 18:59, PALFFY Daniel wrote:

> 
> > I think you can just re-write the boot table completely though (e.g without
> > caring for the flashupd image).  If you want to update the flash then dd in
> > the original and run the updater.exe...  Assuming people screw up and don't
> > save a backup I think the updater.exe does the equivalent of a dd anyhow.
> 
> Ok, I'm doing this. However the first 512 bytes still have to be copied in
> from an original firmware. Do you know the meaning of those few bytes at
> 0x100? The text before doesn't seem to be important, but the first dword
> seems to be some magic number (it's included as a literal in the loader
> right after 0x55aa - the PC boot sector magic. I haven't disassembled it
> further yet). The other values seem to be required, too.

That reference in the bootloader is for the pdisk command which I would
assume to be a command to partition the disk.  Its not called by the
startup.  I can't see any other references to it in the bootloader...

> > Anyhow I'll take a look see in a few hours and see about giving it a whirl.
> 
> Try this instead!
> 
> Oh, I've nearly forgotten: This version can load up to 5 images, any of
> which can be the default, the others are load for the four keys on the top
> (or around the wheel).
> 
> PS: I should really read ARM documentation before writing a boot loader...
> It's really funny to find out the hard way that the address of the
> current instruction is (pc & ~3) - 8

:)

<http://www.arm.com/techdocs.nsf/html/ARM7Docs>

The one called ARM7TDM_Rev4.pdf covers pretty much everything you need
to know.

cheers,
bern.