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

[Krzysztof Kozlowski]

On Sun, Sep 25, 2016 at 09:34:45AM +0200, Krzysztof Kozlowski wrote:
> 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:
> http://forum.xda-developers.com/showpost.php?p=47234165&postcount=220
> https://smyl.es/samsung-galaxy-iii-s3-gt-i9300-jtag-leaked-document-how-to-repair-soft-bricked-galaxy-s3/
> 
> 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...

Hi Wolfgang,

Few more info from my side. It is (rather) not possible to just flash
GT-I9300 with U-Boot. It still requires S-Boot as a primary bootloader
(probably different than the stock one). I think such binary S-Boot was
published along with Tizen images for Trats2 (called RD-PQ). These
images however started to disappear from download.tizen.org. You can
still find some, e.g.:
http://download.tizen.org/releases/system/Tizen_RD-PQ_System_20130716_1.tar

(better download it soon :) ) This 'tar' should be uploaded through
Lthor (also from tizen.org) however it might require appropriate
Partition Information Table (PIT).
On Tizen Wiki you might find some guides for flashing/upgrading-PIT on Trats2.

However, please be careful, as all of these steps (and linked binary) are
targeted to existing RD-PQ/Trats2 boards. They are not intended as a
way of converting GT-I9300 into Trats2. The conversion might work but...
it might not.

Before playing with it, I think it would be wise to have the emergency
recovery procedure (with SD card) ready.

Best regards,
Krzysztof