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Re: Problem netbooting a prep machine



On Thu, Dec 23, 2004 at 10:13:30AM +0100, Philippe Guyot wrote:
> On Wednesday 22 December 2004 19:21, Sven Luther wrote:
> > On Wed, Dec 22, 2004 at 12:13:29PM +0100, Philippe Guyot wrote:
> > > [snip...]
> > >
> > > [snip...]
> > >
> > > > A few hexdump later....
> > > >
> > > > All seems fine in the headers I have examined.
> > > > Entry point offset points to smthing I believe the start of code (no
> > > > desassembly yet..)
> > > > Load image length
> > > > Flags ( showing big endian for the code)
> > > > Similar for file vmlinuz...., file  zImage from Leigh, x41 boot
> > > > partition of my 43P-140 (whith addition of "root=..." done whith
> > > > preptools), memory after loading using OF .
> > >
> > > I had a look on the boot partition native AIX.
> > >
> > > Besides the AIX logical volume control block, things are the same as
> > > described in Leigh's doc : PC compatibility blok, Entry point offset,
> > > Load image length and so on.
> > >
> > > Once loaded ("load disk"), the memory mapping is the same, flags are the
> > > same, registers are ok (ppc points on entry point ). Image loaded is
> > > greater than vmlinuz..... so I don't think its a size problem.
> > >
> > > And AIX boots, of course.
> > >
> > > Remembering that yaboot (ELF) loads and goes (not very fine) I have no
> > > idea more.
> > > Just a difference/bug  in this OF whith the client interface ? Something
> > > in Linux code not accepted here ?
> > > Should it be this strange thing: RSPC between PReP and CHRP ?
> > >
> > > > I am wondering if I could be able to write a little piece of code for
> > > > testing if it could be load-and-go'ed but I have no experience of that.
> > > > May I use some makefile or equivalent ?
> > >
> > > That seems  rather difficult for me but I am searching.
> >
> > Notice that i heard rumors that some PReP boxes are not able to boot
> > kernels (including initrd) bigger than 4MB.
> 
> That's true with open firmware 1.x.x and 2.x.x (kernel loaded at 0x100000 and 
> OF uses 0x400000 so if size > 3 MB it crashes)  and in this case you have to 
> modify real-base; but I have a 3.3.9 which should be able to deal with bigger 
> kernels.
> 
> And the AIX-thing booted is more than 5 MB in size. 

Ah, what about the initrd size ? It is rather big in those kernels ? 

> 
> > Could you try the netboot-small
> > kernel (it will nto work, probably, but it should boot).
> 
> Do you mean this one ?
> 
> ftp.debian.org/debian/dists/testing/main/installer-powerpc/rc2/images/powerpc/netboot/vmlinuz

Nope, this one : 

  ftp.debian.org/debian/dists/testing/main/installer-powerpc/rc2/images/powerpc/netboot-minimal/2.4/vmlinuz-prep.initrd

> Oh, I already tried that but with same results.  

BTW, you do have a serial console to look at the early messages, or not yet ? 

Friendly,

Sven Luther



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