Re: BeagleBone Black , u-boot, and zImage

[Denys Dmytriyenko <denys@ti.com>]

On Fri, Aug 15, 2014 at 06:47:12AM -0300, Diego Sueiro wrote:
> Carlos,
> 
> On Thu, Aug 14, 2014 at 5:20 PM, Denys Dmytriyenko <denys@ti.com> wrote:
> 
> > On Thu, Aug 14, 2014 at 10:09:01PM +0200, Carlos Rafael Giani wrote:
> > > On 08/14/2014 10:04 PM, Denys Dmytriyenko wrote:
> > > >On Thu, Aug 14, 2014 at 09:53:34PM +0200, Carlos Rafael Giani wrote:
> > > >>Hello,
> > > >>
> > > >>after building a rootfs for the Beaglebone Black, I see the
> > > >>following files in the deploy folder for the machine:
> > > >>
> > > >>MLO
> > > >>u-boot.img
> > > >>u-boot-spl.bin
> > > >>zImage
> > > >>
> > > >>as well as other symlinks with "-beaglebone" attached to their
> > filenames.
> > > >>
> > > >>What should I copy, the SPL bin, or the .img u-boot binary?
> > > >>Also, u-boot tries to load a uImage, even though a zImage was built.
> > > >>There is also no uEnv.txt file.
> > > >>Do I have to write one to be able to let u-boot load the zImage, or
> > > >>should it work out-of-the-box?
> > > >Depends on the rootfs image you are building. Most images that are
> > based on
> > > >core-image-base will take care of deploying necessary pieces into the
> > rootfs.
> > > >But core-image-minimal is special and very bare-bone, so extra manual
> > steps
> > > >are required.
> > > >
> > > >Regardless of the rootfs image, you'd need MLO and u-boot.img to be
> > located in
> > > >the first FAT partition of your SD card or eMMC flash.
> > > >
> > > >Then, if your rootfs does not already have zImage and the necessary DTB
> > files
> > > >in the /boot directory, you have to place them there (i.e.
> > core-image-minimal)
> > > >and you are ready to boot. All the defaults will work for
> > out-of-the-box in
> > > >this case. No uEnv.txt is necessary, unless you need to do something
> > extra
> > > >special...
> > > >
> > >
> > > Oh, I just built core-image-base .
> > >
> > > So I should use the .img and not the SPL .bin? I was wondering if
> > > the SPL bin is a newer binary that will eventually replace the .img
> > > one.
> > >
> > > But when I use the .img file, it turns out that it tries to load a
> > > uImage, even though a zImage was built. Simply setting the bootfile
> > > env var to "zImage" won't work, because the u-boot script will try
> > > to boot with the incorrect command.
> > >
> > > I am trying to rule out that something went wrong in my build, that
> > > something is wrong in my setup. If I build core-image-base , the
> > > resulting u-boot.img should automatically load a zImage, not a
> > > uImage, correct?
> >
> > u-boot-spl.bin, while named weird, is a special SPL binary (i.e. MLO) for
> > UART
> > booting - loading u-boot and the rest over serial. They are similar in
> > sizes
> > with MLO...
> >
> > The real u-boot.img should boot zImage by default - make sure you are
> > building
> > the correct one from meta-ti. The one named u-boot-ti-staging is preferred,
> > but u-boot_2014.07 should also be fine.
> 
> 
> Here you have some instructions on how to "cook" an sdcard for beaglebone
> black:
> http://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/README.hardware

Well, that README I wrote specifically for Poky and meta-yocto-bsp. And Carlos 
was looking for meta-ti specifics. The instructions are mostly similar, but 
require adjusting for things like uImage vs. zImage and such...

-- 
Denys