Thread: Garmin GB Discoverer 1:50K - Full Coverage (2.00)

Originally Posted by demontazor

Hi Catymag, I tried to unlock with fast IMG unlocker and it gets to 70 and then it stops. I am not the only one with this problem.
First I downloaded the files from the first page (they were locked), then I downloaded the last files from the 3th page (I thought the last files were unlocked) but no go.
So, if it is so easy, why not upload the unlocked files.

As Ballebar said, a DIV BY ZERO exception error will occur when Fast IMG Unlocker is used with this map.
None of the current unlocking tools available here (or from other public forums) can unlock this map.
This is because they all currently use GarminUnlocker.exe to unlock the individual map tiles within the original gmapsupp.img file.
As in this map, it only takes one map tile that is to large in file size and GarminUnlocker.exe will fail to unlock it.

This problem will get more & more common as Garmin releases updates to some of their map products (mostly large file sized Topo & BlueChart g2 Vision maps).
So get used to using the keygen instead when you can (if the MapID < 2200).

Using locked img files are prefered (when you can use them) for several reasons...
You are using an unaltered original img file of the map as released by Garmin.
You are unlocking it with a unl file as designed by Garmin.
You are assured that all the features the original map img file contains will still be available and function correctly.

Oké Ballebar, tell me, what is the benefit of a LOCKED .img to a unlocked .img. I don't want to use it with my laptop or any program (mapsource ....).
Just my Dakota 20.

Hhmmm, I have 24 unlocked topo's and CN maps, and they all function correctly. So no Great Britain, but thanks for the reply's.

It works on a Dakota 20.
But it doesn't work on an Oregon 450 (latest firmware 3.80). I'm 100% the generated UNL file is correct.
I read somewhere about a new security method Garmin is using for new maps and that devices with recent firmwares are checking on this. Something about a certificate file (.gma I think) you also need for recent maps
Could this be the reason?

I used Jetmouse 1.5 with checksum check fix.

Originally Posted by redcap_be

It works on a Dakota 20.
But it doesn't work on an Oregon 450 (latest firmware 3.80). I'm 100% the generated UNL file is correct.
I read somewhere about a new security method Garmin is using for new maps and that devices with recent firmwares are checking on this. Something about a certificate file (.gma I think) you also need for recent maps
Could this be the reason?

I used Jetmouse 1.5 with checksum check fix.

I have the same problem with Dakota 20 software 3.30 (can't unlock map).

@demontazor: here it work perfect, also on Dakota 20 software 3.30 .
@Ballebar: it works also on Oregon 450 software 3.80 (latest). I forgot to paste one character of the GPS unit ID in Jetmouse.
Thanks!

ok I'll doublecheck this evening.
thanks

Thanks I have it working on 550T by getting unit code from Basecamp then putting that in jetmouse to generate unlock code using FID= 2043 . Then put unlock code in UNL file with map on SDcard and bingo. Great site thanks for all the info I have gleaned to get to this stage. I am now going to see if I can combine this with city navigator maps.
Note:I have tried all mentioned ways to get SD card ID but failed at every attempt. I have another laptop to have a try this afternoon.

Ocicat