[maemo-developers] N800 won't start

From: Eero Tamminen eero.tamminen at nokia.com
Date: Mon Mar 19 10:48:22 EET 2007

(cross-posting to developers)

Besides buggy 3rd party packages or software, there are several (rare)
reasons why the N800 might not boot.

Important things in the symptoms:
- Does the device just turn itself off, or does it reboot?
- Exactly how many seconds this happens after device is powered on?
- Does the device show the progress bar at startup?
- Does the device get to Desktop until it reboots?

Below I'll go through all bootup problems found so far and tell
how to deal with them before the next release (where these are fixed)
is released.

ext Marius Gedminas wrote:
> On Sat, Mar 17, 2007 at 12:33:54AM +0100, Paolo Casarini wrote:
>> When i turn on my n800 the progress bar doesn't come up and it never
>> starts. After a minute the screen become black for a second and then
>> back white with the Nokia logo.

Have you timed this properly?  I think this time should be only a bit
over 1/2 minute and is most likely caused by kernel JFFS2 file system
taking too much  time when garbage collecting (which happens when a lot
of data was earlier written so that flash was about full and then most
of it was removed) -> as a result device HW watchdog reboots it (HW
watchdog has 1/2 min timeout).

With the first release this could sometimes (_very_ rarely) happen when
the rootfs was mounted i.e. before progress bar.  In the second release
it could sometimes (_very_ rarely) happen while device was booting
(i.e. when progress bar was shown).  This latter case should also be
fixed in the next release. It's possible (but not guaranteed) the device
recovers from this by rebooting again a couple of times.

You cannot disable the device HW watchdog, so if this isn't fixed by
just  device rebooting itself several times, you need to reflash the

> I've seen a n770 act like this.  Plugging in the charger, waiting
> several seconds, and then turning it on helped.

If the battery is too low, the device is turned off much earlier.
And yes, charging helps for that.  It's not a bug. :-)

There was also a bug in N800 that if the device rebooted 10 times a row,
it's shut down to save battery (expected behaviour).   However,
sometimes on powering it up again after that kind of a shutdown, it
thought that it had already rebooted again those 10 times and shut
itself again immediately.  This happens *exactly* 6 secs after device
boot and can be worked around & is fixed in next release.  It's very
rare because first you need to get your device in reboot loop.

Workaround before next release is setting the device to R&D mode (when
this 10xReboot check is disabled) with the flasher tool, booting the
device and fixing the issue that caused the earlier 10 succesive
reboots.  If the behaviour does not get then back to normal when
disabling R&D mode[1], backup your data with R&D mode on, turn the R&D
mode off and reflash the device.

[1] R&D should not be enabled all the time for various reasons
     on devices which are intended for normal use. Note also that
     R&D flags are not changed when device is reflashed!

>> I tried to remove the internal or external SD card, but the behaviour is
>> the same. I also tried to use the battery of my old 770 but the N800
>> won't start.

This is one more bug very rare bug, which is related to
metalayer-crawler (data indexer for the media player) starting to index
MMC immediately on boot when the card is mounted and not handling
corrupted FAT filesystem properly. As a result the device is unstable.
Corrupted card FAT file system can be fixed with Linux or Windows FAT
fcsk program.

There has been on claim on the list that the FAT is OK and there's
instead an issue with some specific file on the card, but nobody's yet
verified this issue or named format of or given link to a file that
could cause this kind of a problem.

>> I've to reflash the tablet or I've to go to a Nokia point?
> A reflash will help only if you've installed or upgraded some software
> package that broke it.  It's something worth trying before you go to
> Nokia.

Doing backups and restoring them from the device control panel is
easy, and you anyway need to use that when flashing the further
releases (with new features), so I highly recommend doing them.

Note that if you install some 3rd party software, it's possible that it
fills the device Flash[2] so full that it doesn't anymore function.
This can have symptoms similar to the JFFS2 issues explained above.
This should be _very_ rare also, but please make a backup of your data
& settings before installing 3rd party software!

There was also a bug in the RSS applet that it sometimes crashed the
Desktop (when it had fetched from added gnome.planet feed image URLs
containing several "http://" strings in the same URL).  This resulted
in device reboot loop.  The applet is fixed in next release also.

	- Eero

[2] Debian package management isn't completely robust against filling
     the disk, there are some cases when it doesn't handle it.  All
     packages having their own pre/postinst scripts or storing files
     that don't appear in package management need to take special case
     not to fill Flash (actually they should leave several megs free,
     JFFS2 stops working for the users if there's only about 2MB
     free space.  As packages are installed as root, they can fill
     the file system more completely).

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