[Gta04-owner] Broken devices

[Dr. H. Nikolaus Schaller]

Am 03.11.2011 um 22:06 schrieb Christoph Mair:

> On Thu, Nov 3, 2011 at 8:32 PM, David Lanzendörfer
> <david.lanzendoerfer at o2s.ch> wrote:
>>>> Can you boot the device over seriell?
>> There only is one Answer "60".
>> Then it dies...
> 
> This usually means that the CPU is working but could not find a device
> to boot from. Did you verify that the SD card works in your GTA04?
> You might want to try other scripts than the one provided by Nikolaus
> to format the card and you might try different cards. Just make sure
> that the MLO ist the first file you copy onto the card. Also try a
> different MLO version. The one in the hw-tester(?) directory seems to
> work. Unstable doesn't, IIRC.

Yes, the one on unstable appears to be broken. I will check that in the
next days.

There is also a trick to find out if MLO is being executed.
The backlight of the display does a short flicker (white-black-white).

> 
> If all this fails, you could try to boot using the serial cable. Rene
> already sent a link to instructions on how to do it.
> 
> How did you power the board? Recharge the battery if necessary and if
> possible measure the voltage on the VBAT testpoint using an
> oscilloscope. You should get a steady line with a slight voltage drop
> once the board gets powered. The voltage should never fall below 3.5V.
> 
> If you use an external power supply, please measure the voltage at the
> battery connector; thin wires and bad contacts cause a heavy voltage
> drop which might reset the unit during power on. I configured my PSU
> to about 4.1V to get approximately 3.5V at the battery connector.

What else could be a problem? There could be some X-loader in NAND
flash that does not work. If you press the AUX/USER button and leave
it pressed after inserting the battery for some seconds, it forces the Boot ROM
to change the search order to search the SD card before any NAND flash.

Nikolaus