[U-Boot] [PATCH 00/14] Nokia RX-51 support

[Sergey Lapin <slapin@ossfans.org>]

On Wed, Jan 25, 2012 at 11:00:34PM +0100, Marek Vasut wrote:
> > On Wednesday 25 January 2012 22:29:16 Marek Vasut wrote:
> > > > On Wednesday 25 January 2012 21:56:37 Marek Vasut wrote:
> > > > > > On Wednesday 25 January 2012 19:20:01 Marek Vasut wrote:
> > > > > > > So why not just replace the bootloader right away?
> > > > > > 
> > > > > > Booting process on n900:
> > > > > > 1. Omap bootrom
> > > > > > 2. Nokia X-Loader
> > > > > > 3. Nokia NOLO Bootloader
> > > > > > 4. Linux kernel
> > > > > > ...
> > > > > 
> > > > > To make it clear, I own N900 myself ;-)
> > > > > 
> > > > > > Nokia X-Loader and NOLO are stored in first nand part. It has size
> > > > > > 128kB. Nokia X-Loader is signed (size 14.5kB), so cannot be
> > > > > > replaced. NOLO bootloader is not signed (so theoretically can be
> > > > > > replaced), but size is limited to 113kB. I do not know how to
> > > > > > compile U-Boot binary with size < 113kB...
> > > > > > 
> > > > > > Size of part where is stored linux kernel has 2MB and it is enought
> > > > > > for
> > > > > > U-Boot with kernel image (~200kB + ~1.6MB). Also U-Boot can boot
> > > > > > kernel
> > > > > > from eMMC/SD.
> > > > > 
> > > > > You didn't answer my question, so again ... why can't you replace
> > > > > NOLO? Because there's the 113kb limit? Use SPL then.
> > > > 
> > > > I only tried to boot U-Boot in qemu wich increased boot part - but not
> > > > worked. (NOLO in qemu can boot u-boot without problems). So NOLO do
> > > > some extra work - which I do not know... Also limit is problem to test
> > > > on real n900.
> > > 
> > > What do you mean? Did you crack yours open? Can you connect JTAG to the
> > > device? I didn't check on mine.
> > 
> > I have no idea if N900 has JTAG. And I think that nobody cracked X-Loader
> > yet.
> 
> What do you mean, you don't need xloader, u-boot SPL can replace it.

Yes and no. No, becaue you nor I have no Nokia's signing key(s) to sign
SPL binary for OMAP's secure boot ROM. IIRC N950/N9 is even more strict
regarding that, am I right?

> > 
> > NOLO bootloader can be replaced/flashed via flasher-3.5 app throw USB. Also
> > when NOLO is damaged (or cleared/replaced) it can restored - coldflashed
> > again via flasher-3.5.
> 
> I know. So ... ? Basically you can use the TI flashes too since it all goes 
> through the bootrom, right?
Butrom requires signed binary.
> > 
> > What I tried:
> > I created mtd image where was X-Loader, NOLO and U-Boot. QEmu RX51
> > successfull booted this image and I got serial console and video screen
> > output.
> > 
> > But when I created mtd image where was only X-Loader an U-Boot, QEmu RX51
> > was unable to boot (it freezed).
> 
> Why? Where? You know you can debug U-Boot in QEMU with GDB and diag the problem 
> properly?
Any volunteers? (I own N900 too, ah, I own 3 of tham, damnit)
> 
> > 
> > So NOLO executing some code which inilialize board or someting else which
> > must be done in U-Boot board code. There is no documentation or info about
> > NOLO, so I cannot create working NOLO replacement.
> 
> Yes you can, either observe it or disas it.
> 
> M

All the best,
S.