Urgent - Nuvi 770 'Can't unlock Maps' error message

[dougconran]

I'm going on holiday to the US on Sunday and my Garmin Nuvi 770 has suddenly started playing up.

When I switch on I have to go through some inititalisation process selecting Locale and then get a message saying - 'Can't Unlock Maps'

I now have no addresses, no POIs no nothing.

HELP - what do I do (other than chuck it in the river)?

Doug

[PhilHornby]

The unlock information is initially read from a file into some inaccessible part of memory and the file in which it is supplied is no longer needed. For some reason, Garmin delete this file before shipping the unit. This is fine until the moment it loses the info and it needs to be reloaded.

The 770 is the one with the US and Europe maps, isn't it? - in which case there are two unlock files involved. Have you lost access to both sets of maps, or just one of them.

You will probably find GMAPPROM.IMG and GMAPPROM1.IMG in the \Garmin directory. You need to create corresponding GMAPPROM.UNL and GMAPPROM1.UNL files (using notepad). These need to contain the 25 digit map unlock code. Garmin used to supply these on a Yellow voucher, but not any more -- If you've registered the unit, you should be able to find the information at http://my.garmin.com

(I can't remember which file is for which map...)

[Should you happen to have Mapsource, I think its 'Unlock Wizard' can perform this operation for you].

If you've not yet registered the unit, beware that it may insist on 'upgrading' the firmware first. You absolutely DO NOT want to do that!! V4.00 and V4.01 introduce multiple bugs and there is no downgrade path.

(The workaround for that, is to let the upgrade commence, but delete \Garmin\GUPDATE.GCD from the Nüvi BEFORE it is rebooted/disconnected from the PC.)

You may have more questions ...

[dougconran]

Phil, thanks for your reply.

Fortuitiously I was already registered with Garmin and so was able to get the unlock codes from them (after putting in the serial number of my device).

Like you say, it decided that I should 'benefit' from the latest version of the firmware but, fortunately(?) it upgraded to 4.10 which, as far as I can make out, is not too bad (certainly better than having no maps).

The 770 does have both Europe and USA maps, which is why I got it and the reason for the panic, I'm off on holiday to the States tomorrow!

For the record, for anyone who comes after me with this problem, this is what you need to do:-

1. Go to http://my.garmin.com
2. Log in (or register if you do not yet have an account)
3. Click on 'MyMaps'
4. Click on 'Manage Maps'
5. Copy all unlock codes (1 per line) to a text file
6. Save the text file as gmapprom.unl (you only need the one file)
7. Connect the Garmin device to the PC
8. Copy the gmapprom.unl file to the Garmin directory on the device
9. Disconnect the device from the PC
10. After it displays the 'Where to' / 'View Maps' screen switch it off, pause for a bit and then switch it back on.

If all else fails go to 'Search Support' on the Garmin website and enter "Can't Unlock Maps"

Good Luck - and thanks Phil

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