Trying to boot custom kernel on Wink Hub (i.MX28)

[Rogan Dawes]

Thank you so much for the response! It is much appreciated!

I do hope to get JTAG working on the Hub v1, and then will be able to try
to build a modern U-Boot which I can flash.

Regards,

Rogan


On Thu, 15 Jun 2023 at 22:01, Fabio Estevam <festevam at gmail.com> wrote:

> Hi Rogan,
>
> On Thu, Jun 15, 2023 at 9:00 AM Rogan Dawes <rogan at dawes.za.net> wrote:
> >
> > Hi folks,
> >
> > I am trying to boot a custom kernel on a Wink Hub v1, which has an i.MX28
> > CPU, and is running U-Boot (U-Boot 2014.01-14400-gda781c6-dirty (Apr 30
> > 2014 - 22:35:38)).
> >
> > I have tried compiling my own modern kernel and putting it in place of
> the
> > vendor (Linux version 2.6.35.3-flex-dvt) kernel on the flash chip, but
> when
> > loading, I simply get the expected U-Boot loading messages, but then
> > nothing at all from the serial port after that.
> >
> > I'm trying to figure out where my problem is most likely to be. As far
> as I
> > am aware from long-ago poking at U-Boot, the way that U-Boot passes
> > arguments to the kernel has changed recently? Previously it was ATAGS,
> and
> > now it expects a Device Tree Blob? Might this explain the failure to boot
> > that I am seeing? And yes, I understand that given that
>
> Yes, to boot a modern kernel, you need to generate a devicetree for
> the Wink Hubv1 board.
>
> Then you build it and generate a .dtb file.
>
> To boot zImage + dtb using an old bootloader that does not support booting
> dtb,
> you would need to select the following options in the kernel:
>
> CONFIG_ARM_APPENDED_DTB=y
> CONFIG_ARM_ATAG_DTB_COMPAT=y
>
> And then:
>
> cat arch/arm/boot/zImage arch/arm/boot/dts/imx28-wink-hub-v1.dtb >
> zImage_with_dtb
>
> And then boot zImage_with_dtb as you do with 2.6.35.
>
> Ideally, you should also port a modern U-Boot version, which supports
> dtb by default and then you don't need the
> steps above.
>
> Take a look at board/freescale/mx28eevk support for a reference.
>
> Regards,
>
> Fabio Estevam
>