[elbe-devel] rootfs partition image?

[Manuel Traut]

Hi Norbert,
 
> On 30.11.2015 14:39, Manuel Traut wrote:
> >
> >>At the moment, we only create filesystem-images for ubifs.
> >>There is no support for writing an own boot-sector.
> >>
> >>I think support for sth. like
> >>--8<--
> >><images>
> >>   <msdoshd>
> >>     <name>..</name>
> >>     <size>..</size>
> >>     <binaries>
> >>       <binary bs=1024 seek=8>/tmp/u-boot-with-spl.bin</binary>
> >>     </binaries>
> >>     <partition>
> >>       <size>1G</size>
> >>       <label>rfs</label>
> >>       <offset>1M</offset>
> >>     </partition>
> >>   </msdoshd>
> >></images>
> >>--8<--
> >>
> >>would be nice.
> Looks good to me.

The related source is in elbepack/hdimg.py

In line 330 we continue, if the tag is not partition. There we need
a check for the new 'binary' tag and implement the dd.

The offset parameter of partition needs to be evaluated and used in
the parted code some lines below.

Do you think you are able to implement this?

> I saw that there is some special grub support in elbe. What does
> that offer? Can grub be installed to the boot sector? How would that
> work?

If the grub tag is set in an image, we install the debian package
grub-pc, loopback mount the filesystems and run 'grub-install' inside
the chroot that installs grub to the MBR of the specified disk-image.

> >>Does anyone have experience with boards that expect to find u-boot
> >>at the beginning of the disk?
> >IMHO this boot-method is popular for Allwinner SoCs?
> May well be. I only know this one specific Allwinner A33 board
> (sinlinx SinA33) that I am working with.
> 
> >I have never used elbe with this kind of boot-method.
> My understanding is that this boot-method is the default on desktop
> systems. I'm surprised that it seems to be rather exotic for
> embedded...

Yes it is :) Typically the bootloader is stored on a raw NOR flash or
on the first (vfat) partition of an SDCard or eMMC.

Regards,

  Manuel