Weird battery (?) problem bricked N900

A friend of mine has recently bought a N900 (via ebay), used it for ~2 weeks
and now got it bricked in somewhat weird way. He said that during normal
use, just while fiddling with menu/apps, suddenly a "charging error" message
appeared (*without* a charger connected!), notification light turned red and
device has switched off by itself, never booting back again.

As soon as I've got his N900 in my hands, I've started with simply trying to
switch it on. It does indeed switch on, however it gets stuck on white NOKIA
splash screen for about 20-30 seconds and then shuts down again. Once
connected to the charger, it gets into infinite reboot cycle, still not
getting any farer than NOKIA splash screen. Note that notification light is
*solid* amber while hooked up to the charger (usually blinks slowly). Also,
what's probably worth noting, while powering up notification light doesn't
turn on all, while this light in my N900 is always turning white for 1-2
seconds before actually switching display on with initial NOKIA splash.
Anyhow, since device actually does switch on, I've tried to reflash a
firmware, discovering shortly after that device doesn't enter usb mode while
pressing "u" key and plugging cable in. Just powers on and nothing happens
at all. Crap. :(

Now very interesting thing happened when I've swapped battery from my own
N900. On that battery it still didn't boot fully (dying on NOKIA screen),
HOWEVER I was able to enter usb flash mode and reflash firmware. Also, while
connecting wall charger it does display usb icon in screen corner for few
seconds. Unfortunately, despite reflashing both OS and eMMC images, it still
doesn't work, simply shutting itself off after 20-30 seconds. :(

Nonetheless, I was very suprised to see that device was acting a little
differenty with other battery in it. Does that give any clue? Is there any
chance to ressurect my friend's N900? Or a warranty repair is the only
reasonable option here?

Any suggestions are wecome. Thanks!

--
Dawid 'evad' Lorenz * http://adl.pl

null://google 'no evil' mail has taken away my random signatures

On Mon, Apr 12, 2010 at 8:26 PM, Dawid Lorenz <adl@adl.pl> wrote:

> Nonetheless, I was very suprised to see that device was acting a little
> differenty with other battery in it. Does that give any clue? Is there any
> chance to ressurect my friend's N900? Or a warranty repair is the only
> reasonable option here?
>

I think since charging is done by software and only starts after booting,
your already charged battery gave the device the juice it needed to go.

As for the continued malfunction, have you tried to reflash everything,
including the eMMC? Might be a corruption in files caused by the successive
attempts to get it up, that could only be fixed by a complete reflash.

Best regards,
--
Cláudio "Patola" Sampaio
IRC: ptl - Yahoo: patolaaa
Campinas, SP - Brazil.

2010/4/13 Cláudio Sampaio <patola@gmail.com>

> As for the continued malfunction, have you tried to reflash everything,
> including the eMMC? Might be a corruption in files caused by the successive
> attempts to get it up, that could only be fixed by a complete reflash.


Yes, as I already said - I've reflashed both fiasco images and that didn't
solve the problem.

--
Dawid 'evad' Lorenz * http://adl.pl

null://google 'no evil' mail has taken away my random signatures

[Dawid Lorenz Di 13. April 2010]:
> [...] He said that during normal
> use, just while fiddling with menu/apps, suddenly a "charging error" message
> appeared (*without* a charger connected!), notification light turned red and
> device has switched off by itself, never booting back again.

No idea yet what to make out of that to come up with a reasonable story.
*could* be a short in battery, heating up the cell and same time losing
capacity and tripping the temperature sensor. It could be a wacky contact in
battery's BSI. Could also be a hardware break in device itself, or even a
software glitch (in bme?). Anyway there's no means the red indicator lights up
without software commanding the LP5523 LED controller chip to do so (remember
that fact for later explanation)


> As soon as I've got his N900 in my hands, I've started with simply trying to
> switch it on. It does indeed switch on, however it gets stuck on white NOKIA
> splash screen for about 20-30 seconds and then shuts down again. Once
> connected to the charger, it gets into infinite reboot cycle, still not
> getting any farer than NOKIA splash screen.

This can be caused by system init or bootloader finding some fishy details in
battery and power state. Also there are other pitfalls that can cause infinite
boot loop. Flashing a new fiasco image should cure most of them. Nevertheless
see below about "Houston, we got a problem" bootcounter issue.


> Note that notification light is
> *solid* amber while hooked up to the charger (usually blinks slowly).

Though you'll probably hear other tales, it's actually a fact the N900 *can*
charge without system booted up, I.E. without any software support from
system. The BQ24150 USB battery charger controller chip is able to charge
battery fully autonomously (though initially with as little as 100mA only),
and it signals this charging state with a hardwired yellow indicator. Later on
during *normal* boot process this hardwired yellow light eventually is
switched off when bme daemon takes control over the charger chip, and also bme
signals mce daemon to do the yellow flashing same moment.

> Also,
> what's probably worth noting, while powering up notification light doesn't
> turn on all, while this light in my N900 is always turning white for 1-2
> seconds before actually switching display on with initial NOKIA splash.

This initial bluish white indicator ramp-up is done by NOLO bootloader, and I
don't know exactly what to make out of the fact it doesn't show on the
defective device. NOLO might decide not to light it up on certain unusual
conditions (e.g. battery too low(1) ), or NOLO is broken, or the whole system
doesn't start CPU due to battery too low (GAIA power management chip won't
start the system when battery voltage is too low(2) - so the basic charging by
charger chip will slowly charge up the battery and system doesn't draw more
power than the 100mA) - but AIUI you see this missing white indicator even
with your good fully charged battery.
[too_low(2) < too_low(1)]

> Anyhow, since device actually does switch on, I've tried to reflash a
> firmware, discovering shortly after that device doesn't enter usb mode while
> pressing "u" key and plugging cable in. Just powers on and nothing happens
> at all. Crap. :(

When system powers up, that means NOLO works, and if NOLO detects "u" hold, it
should enter flashing mode - unless low battery.
So with the considered dead or discharged original cell this behaviour is
somewhat expected.


> Now very interesting thing happened when I've swapped battery from my own
> N900. On that battery it still didn't boot fully (dying on NOKIA screen),
> HOWEVER I was able to enter usb flash mode and reflash firmware. Also, while
> connecting wall charger it does display usb icon in screen corner for few
> seconds. Unfortunately, despite reflashing both OS and eMMC images, it still
> doesn't work, simply shutting itself off after 20-30 seconds. :(

There's been an issue with some counter tripping after 30(?) failed boots.
Maybe somebody else more savvy (jebba?) on that topic can take over to check
if failing boot might be caused by this. You might want to check bugtracker
for this issue.


> Nonetheless, I was very suprised to see that device was acting a little
> differenty with other battery in it. Does that give any clue?

First of all it seems to indicate the original battery is near flat. You
should try (to charge) that considered defect battery in your known good N900,
and if that succeeds then do the check again to see if it still acts
differently than with your known good battery.


> Is there any
> chance to ressurect my friend's N900? Or a warranty repair is the only
> reasonable option here?

Too early to do any honest judgement.
The sudden red indicator is somewhat scary, and it doesn't indicate anything
if you don't see it anymore now - see above for explanation why a working
system is needed to light up that red light.

Good luck
jOERG

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