[Gta04-owner] Trying to flash U-Boot led to a bricked device

H. Nikolaus Schaller hns at goldelico.com
Wed Mar 14 13:06:07 CET 2018


Hi,

> Am 14.03.2018 um 07:47 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> Hi,
> 
> On Mon, 12 Mar 2018 21:56:55 +0100
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> Hi Cnut,
>> 
> [...]
>> Rebooting didn't show again the issues mentioned above. They seem to be a side-effect of migration.
>> 
>> Maybe reflashing the very old boot loader once resets everthing to a state
>> that an upgrade to the new one becomes possible or at least does not fail.
>> 
>> So we still don't know why it failed for you, but we seem to have a procedure
>> to switch back and forth (using two µSD cards with old and latest boot-loader built with current makesd).
>> 
> I guess probably old bootloader flashing new one (because of an
> accidiential boot from nand). And then It might have troubles with the
> script.
> Older uboots e.g. do not recognize the load command, well there should
> be error checks.

Exactly. It might simply not be possible to solve it better since the
shell of u-boot is much less capable than a standard shell + /bin tools.
Mainly there is no "which" command...

Anyways it is just some ripple on the boot log and appears only once
in this special case. So it is not worth finding a fix.

> 
>>> Let's say I have created a sd card with an old boot image and want to test it.  
>>>> See: http://projects.goldelico.com/p/gta04-main/downloads/54/  
>>> In the document behind the link is written for "AUX pressed" with "NAND flashed and MMC installed": It does "MLO:MMC". I assume that is the case I need ot flash from sd card.  
>> 
>> Yes, so that it does not try to run a broken or bad MLO from NAND.
>> 
>>> Does it mean that I have to
>>> - remove usb cable and battery
>>> - put the sd card in the gta04
>>> - press and hold aux button
>>> - insert battery
>>> - and release aux button when something from the sd was loaded (a menu, red screen etc.)
>>> Is the assumption correct?  
>> 
>> Yes, exactly.
>> 
>> And I recognize that this mail contains a lot of material for a HowTo page. Anyone here with a public blog?
>> 
> I think it boils down to follow some instructions exactly to prevent
> accidential boots from bad nand contents regardless of whether you do a
> rescue from mmc or usb. These instructions do not look as if they have
> to be followed exactly in that order. Being shocked because you think
> you have a bricked device does not help for that either. So you need to
> be calm.

Indeed. So far the GTA04 has turned out to be really unbrickable by software.
> 
> The unknown environment is risk factor. But that can be mitigated by
> cleaning it during update. The USB-DFU-way does not use environment
> from flash, so it should work regardlessly.
> It does not even try to
> read some content from there, so it just needs to be able to erase and
> write to nand. Well, you could also compile a mmc-self-sufficient usb
> uboot which does not depend on any information in ram.

But this makes it more difficult to understand the list of files and flashing
u-boot is no longer copying the same binary as the one that has been used
for booting. So I fear that this introduces another potential source of trouble...

> 
> If you know how the boot process works, it is obvious that you have to
> follow these instructions in exact that order.
> 
> So I am a bit unsure how to provide the right amount of information
> here and what it should be. 
> 
> Well, I think I should create a gta04-rescue deb package containing a
> script where you have to acknowledge step by step.

Yes, this is a very good idea!

BR and thanks,
Nikolaus



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