[Sugar-devel] Strange problem, a big size number in xo4's screen.

[Buddhi Tuladhar]

Dear James,

Thank you so much for your guidance and all references. I will try my best
to recover it, since i have not done these types of works before, it will
be difficult for me. Below are the SKU numbers that you asked.

SKU322 CQF51200C5E
SKU326 CQF51300085
SKU322 CQF512000F8
SKU322 CQF51300003
SKU322 CQF51200026
SKU322 CQF512000C6
SKU322 CQF51200C6A

Regards,
OLE Nepal Tech Team.


On Thu, Dec 14, 2017 at 3:16 AM, James Cameron <quozl at laptop.org> wrote:

> G'day Buddhi,
>
> Thanks for your question.  Your question is not about Sugar, but I'll
> reply here because there are some people who may be interested.
>
> This problem is seen with low frequency and has known causes.
>
> Please tell me the SKU, the affected serial numbers, how many laptops
> affected, and how many laptops unaffected?  I use this for measuring
> the problem.
>
> My recommendations are;
>
> (a) now, repair the affected laptops using serial adapter [1] and SPI
> FLASH recovery for XO-4 using CForth [2],
>
> (b) in future, identify laptops likely to be affected (see below) and
> before reflashing remove charger and main battery for 30 seconds,
>
> (c) in future, when firmware reflash does hang, do not turn off,
> instead connect a serial adapter and repair,
>
> (d) now, if the number of laptops is too high, reinforce normal
> precautions for handling and storage.
>
>
> In more detail;
>
> Electrostatic discharge, high altitude radiation, extreme
> temperatures, humidity or physical shock can cause temporary
> malfunction of the CPU, memory, and SPI FLASH chip.  Malfunction
> may be invisible until firmware reflash is started.
>
> Firmware reflash may hang.  At this time some blocks are correctly
> written with new firmware, some blocks are erased, and some
> blocks have old firmware.
>
> e.g. "NNNNNEOOO" instead of "NNNNNNNNN", where "N" is new, "E" is
> erased, and "O" is old firmware.
>
> Combined with your power off, the damage to SPI FLASH data means the
> XO-4 cannot start.
>
>
> In much deeper detail;
>
> The symbol "10" is during startup after CForth has run and before Open
> Firmware has turned on memory management unit and caches.
>
> https://github.com/quozl/openfirmware/blob/olpc/cpu/
> arm/mmp3/resetvec.fth#L143
>
> The symbol "16" is during startup after Open Firmware has unpacked and
> processor cache is synchronised to memory.
>
> https://github.com/quozl/openfirmware/blob/olpc/cpu/
> arm/mmp3/resetvec.fth#L232
>
> Both "10" and "16" can be result of interrupted reflashing.
>
> The full list of symbols is;
>
> "00" CForth before loading Open Firmware,
> "01" CForth after loading but before executing,
> "10" Open Firmware before turning on memory management unit and caches,
> "11" Open Firmware after turning on memory management unit and caches,
> "12" Open Firmware before inflating dropin,
> "13" Open Firmware after inflating dropin,
> "14" Open Firmware with uncompressed dropin,
> "15" Open Firmware after dropin is written to cache, and
> "16" Open Firmware after cache is synchronised to memory.
>
> CForth is in the first block of SPI FLASH, and can be used via serial
> adapter.
>
> References:
>
> 1.  http://wiki.laptop.org/go/Serial_adapters
> 2.  http://wiki.laptop.org/go/SPI_FLASH_Recovery_for_XO-4_Using_CForth
>
> On Wed, Dec 13, 2017 at 03:49:13PM +0545, Buddhi Tuladhar wrote:
> > Dear all,
> >
> > I am facing this strange problem in XO4. Every time i start xo4 a big
> size
> > number appears in screen eg 10,16 . Below i have links of the picture of
> xo4
> > screen. this problem appears after flashing the xo with the custom image
> i
> > build, it is not frequent but sometimes while flashing xo4's firmware,
> it gets
> > stuck in the middle and everything stops. After that only thing i can do
> is to
> > press power button and off it, then after that if i try to on the xo,
> big size
> > number appears. I cannot even go to "ok prompt" to re flash the xo. It is
> > creating a big problem for me. If anyone can guide me to solve this
> problem i
> > would be very thankful.
> >
> > [1]http://download.olenepal.org/xo10.jpg
> > [2]http://download.olenepal.org/xo16.jpg
> >
> > Regards,
> > Buddhi Raj Tuladhar,
> > OLE Nepal Tech Team
> >
> > References:
> >
> > [1] http://download.olenepal.org/xo10.jpg
> > [2] http://download.olenepal.org/xo16.jpg
>
> > _______________________________________________
> > Sugar-devel mailing list
> > Sugar-devel at lists.sugarlabs.org
> > http://lists.sugarlabs.org/listinfo/sugar-devel
>
>
> --
> James Cameron
> http://quozl.netrek.org/
>
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