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  1. #11
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    Usually devices have schematics protecting from writing to memory when voltage becomes low.

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  3. #12
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    Thank you all

    Good tokow about the flash menory writing.
    I will take the nuvi for a test drive today - it is now fully charged.
    Will post the result.
    ============
    Carlos Magalhaes
    Garmin nüvi 3790T

  4. #13
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    Quote Originally Posted by voyager56 View Post
    Usually devices have schematics protecting from writing to memory when voltage becomes low.
    Yes the Nuvi has this, When you use the Nuvi on Battery it will safely switch off when the battery "If I'm Not Mistaken" Gets to about 3%
    We are takling here about someone switching on a Nuvi that has the battery almost flat.
    The symtom is that it gets to loading maps and then crashes and switches off sometimes the crash is logged and sometimes not.
    I've had this happening on 3490 and had to flash region 41 via SD card to fix it.
    I keep backups of regions at every firmware level. "OOPS I havent done it for 8.1 yet"
    The difference between stupidity and genius is that genius has its limits.
    Albert Einstein.

  5. #14
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    dasilvarsa

    Thank for the input.

    I took the nuvi for a road test and it performed OK. It seems that the problems were related to the very low battery charge level.

    I have NO knowledge of these "regions", however. I understand that they are specific areas on the flash memory. Can you elaborate a little on this, please ?
    ============
    Carlos Magalhaes
    Garmin nüvi 3790T

  6. #15
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    There are many regions [rgns] potentially available in garmin units' non-volatile memory, but nowhere near all are used on any one particular device. The most crucial of the regions is rgn41 because of the unit specific data it contains, and this is the region that is referred to when we talk about 'doing an NV Backup'. Some other regions also contain 'personal' data, but many don't. An example of the latter is rgn16 which contains the logo/splash, usually the same rgn16 will be common to all units with the same HWID [although, for example, in 1xxx various logo bins 'versions' do also enable/disable features].

    You've already found out [twice] Carlos how crucial region 41 is to restore your 3790 when it decides to become a 37xx. Do it regularly, at least with every fw update as dasilvarsa said. I try to go even further and back up the entire NV ... i don't always do it, maybe every second or third fw update with just 41 in between. If you'd like to do a complete NV dump of your 3790, here's the kit:
    [Only registered and activated users can see links. ].
    Just unrar it to a clean microSD, insert it with your 3790 fully off [press and hold the on button until you get the prompt], turn it back on, check 'Loader' is displayed and go make a coffee. It takes quite a bit longer than backing up just rgn41 so make sure your battery has enough charge. The file 'ldr.bin' is just the boot.bin of the current v5.00 fw, so make sure you update it when the fw version changes on the unit.
    'Thanking Posts' are banned. To thank someone, and/or to see hidden links and content, use the [Only registered and activated users can see links. ] button below left of the helpful post then refresh your browser [F5 key]. 'Thanking Posts' are banned.
    Please don't spam. Posts serving no purpose other than to thank or to ask about hidden links are trashed or deleted, it's GPSPower's policy. Please don't spam.
    [Only registered and activated users can see links. ] should make their first post as a new Intro Thread in [Only registered and activated users can see links. ].

  7. #16
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    Excellent, Neil

    I avoid doing FW updates because my unit is (now) working properly.
    I think I will do only if its behavior becomes erratic or incorrect.
    But wil do a backup.

    Question: how to RESTORE the backup ? Is tehre another utility for this task ?

    Thank you.
    ============
    Carlos Magalhaes
    Garmin nüvi 3790T

  8. #17
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    You mean to restore using a Non Volatile backup i guess. Provided the unit can still read from the media card to take commands from update.txt, to restore a nv region [41 being the most likely] the txt file would read something like this:

    xrgn,41,1:/41.bin
    reboot

    Where in that case the 41.bin file to be written to the unit would be placed in the root of the sd.

    If you wanted to also first backup your existing region 41, a two step command:

    rrgn,41,1:/41_backup.bin
    xrgn,41,1:/41.bin
    reboot

    Then the unit's region 41 would be overwritten after firstly being backed up.

    To be absolutely safe, the backup and overwrite can of course be done separately.

    More info if you need it is here Carlos: [Only registered and activated users can see links. ] [where your first 'model loss' thread gets an honourable mention and a link] and here: [Only registered and activated users can see links. ] for some more in-depth info on commands from sd generally. If you're still hazy on it, post again in the Backup Region41 thread. Cheers.

  9. #18
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    Yes !
    I'm learning a lot, here.

    Thank you.
    ============
    Carlos Magalhaes
    Garmin nüvi 3790T

 

 
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