As usual, I prefer writing down what I did to solve a particular problem or set of problems so that I can myself refer back to it for solutions in future and someone having similar/any troubles can use this as a starting point to try and fix the problems faced. For me, the problems started when my wife started complaining about my Garmin Nuvi 2545LMT not working properly.

There were basically 2 problems with it. It needs the full address to really search for the location and the maps were old (2013.10). So basically I fired up the webupdate in a Win7 machine and started with the updates. It took a whole lot of time (almost 8 hours) before I knew the outcome of the update. The update brought its own problems.

The 2545 firmware was updated to version 8.20 BUT, it removed my supplementary gmapsupp.img file from the device as it needed more space for the new 2015.40 maps. And somehow, it was not able to recognize my separate Nordic maps collection later on. Now I was stuck with an updated map for CN with no usability of Nordic maps. Also the device stopped recognizing maps loaded on SDCards after the update. After much frustration and searching on the net, I figured out the following.

1. I had to go back to the previous version of the firmware which was working fine (7.90).
2. Put the Nordic maps on the internal memory as gmapsrom.img
3. Load the CN maps on external memory as a gmapsupp.img

Reason for doing the switch was that most of my travelling is in Nordic regions and I can safely remove the external SDCard when roaming in Nordic regions. That helps me with faster bootups, faster GPS fixes and responsive device. So below are the steps that needs to be done.

Plugin the unit on a Linux machine (as my windows always loaded as an emulated drive even if mass storage was enabled. Hence I was not able to access the hidden .System folder). Make sure you do a backup of the .System folder before starting the below mentioned procedures. Once the backup is done, head over to http://gawisp.com/perry/nuvi/ and download the firmware for your device. A word of caution, flashing wrong firmware on wrong device will make your device unusable. Of course there are ways to recover (one can search google for that). Take the proper GCD file and put it as GCDUPDATE.GCD file in the hidden .System folder. You can overwrite the old file if any exists.

Now reboot the unit, you should get a warning about installing an older version of the Software and loosing data. Say yes and proceed. Once done, browse through the filesystem and remove unnecessary files to free up the much needed space. Candidates for removals are EULA (other than you language of choice) and help files. Now I put my nordic maps as gmapsrom.img in the .System folder. Formatted my SDCard to FAT32 (mkfs.vfat /dev/mmcblk0), created a Map folder (check your GarminDevice.xml for the right path) and put the gmapsupp.img (CN maps on that one). Of course my maps were unlocked. Locked maps will not work. Unlocking of Garmin maps is a topic discussed a lot in gpspassion so head over there and learn (google is your best friend).

So, after all these juggling, my GPS is finally working. I don’t see any major updates in 8.20 that warrants me to use that version. 7.90 is good enough for me and will stay on my unit.

Cheers and Happy GPS (hacking!) 😉