Re: [PATCH] ARM: dts: exynos: Add reboot reason support for Trats2

From: Krzysztof Kozlowski
Date: Sun Sep 25 2016 - 03:34:56 EST

On Sat, Sep 24, 2016 at 11:04:49PM +0200, Wolfgang Wiedmeyer wrote:
> Krzysztof Kozlowski writes:
> > On Thu, Sep 22, 2016 at 08:59:03PM +0200, Wolfgang Wiedmeyer wrote:
> >>
> >> Krzysztof Kozlowski writes:
> >>
> >> > On Thu, Sep 22, 2016 at 06:48:35PM +0200, Wolfgang Wiedmeyer wrote:
> >> >> This allows to reboot the device into recovery mode and into the download
> >> >> mode of the bootloader.
> >> >
> >> > Which bootloader? Probably UBoot... or Samsung stock one? Could you put
> >> > that information here?
> >>
> >> I'm only working with the stock one. I was under the impression that the
> >> stock bootloader cannot be replaced on a i9300 because there's a
> >> signature check. Is UBoot loaded after the stock one on Trats2 or how
> >> does this work? I didn't find information on that.
> >
> > +CC Marek,
> >
> > Trats2 is working with U-Boot. Just U-Boot. However I never converted S3
> > into Trats2 on my own. I always used targets prepared to be "Trats2"
> > type.
> It would be awesome to be able to run U-Boot on i9300. Is there a way to
> test this by not risking to brick the device, e.g. by booting from the
> SD card? Then I could send an updated version of the patch that is
> compatible with U-Boot :)

I don't think the stock bootloader supports chaining another bootloader
from SD card. There is a way of booting from SD card by shortening a
resistor but it is an emergency rescue procedure to overwrite existing
bootloader with data from SD card (to restore device). This thread might
be interesting:

On xda-developers you might find more data about this (including the
procedure for emergency restore from SD card). Somehow people flash and
unbrick their devices when playing with CyanogenMod...

Best regards,