How to unlock Nuvi 2595lm?

Hi folks!
I have Nüvi 2595 LM, Hardware version: Nuvi 2595 C2p2 i V8, N TE
Unit Software Version: 8.30 GPS Firmware: 4.14.10

When I put a gmapsupp.img to Garmin folder in SD, another device (Nuvi
2599) reads a map, but this 2595 does not read the map. What could be the
reason? I had earlier Nuvi 2595 lmt, and it did read similar maps without
a problem.

Edit:

I tested with replacing Europe with unlocked Australia and New Zealand to
.system; changed unlocked gmapsupp.img to gmapprom.img and put also
gmapsupp.img to Garmin folder in SD. The device opens, loads the map but
the map list is empty. Same unlocked gmapsupp.img works in Nuvi 2599. Is
there something in 2595 I do not know?

Edit:
Hi! I am wondering is there a difference between Nuvi 2595lmt with latest
firmware 8.2 and Nuvi 2595lm with firmware 8.3. I feel 2595lmt (firmware
8.2, from 2012) reads unlocked maps straight from Garmin folder in SD. It
seems that Nuvi 2595lm (firmware 8.3, released 2016) does not read
unlocked maps. In my 2595lm, there is Europe map preinstalled, and it does
not read unlocked City Navigator Australia. I guess the firmware from 2016
includes any protection which affects the difference. What could I do that
2595lm will show the unlocked maps?

On an SD card put the gmapsupp.img in a folder called Map Check your garmindevice.xml it show where everything goes
<DataType><Name>SupplementalMaps</Name><File>
<Specification><Identifier>IMG</Identifier></Specification>
<Location><Path>Map</Path>
<BaseName>gmapsupp</BaseName>
<FileExtension>img</FileExtension>
Try putting this small sample <20Mb in the Map folder on your SD card

Hidden Content

This board requires you to be registered and logged-in to view hidden content.

Thank you for this help. I put the img to Map folder in SD card. However,
the devices does not show the map in the map list? I tested also Australia
& new zealand gmapsupp.img, not show a mmap. The device loads maps while
opening but not show them? In my garmindevice, rows are:

<DataType><Name>SupplementalMaps</Name><File><Specification><Identifier>IMG</Identifier></Specification><Location><Path>Map</Path><BaseName>gmapsupp</BaseName><FileExtension>img</FileExtension>

kaleton wrote:Thank you for this help. I put the img to Map folder in SD card. However,
the devices does not show the map in the map list? I tested also Australia
& new zealand gmapsupp.img, not show a mmap. The device loads maps while
opening but not show them? In my garmindevice, rows are:

<DataType><Name>SupplementalMaps</Name><File><Specification><Identifier>IMG</Identifier></Specification><Location><Path>Map</Path><BaseName>gmapsupp</BaseName><FileExtension>img</FileExtension>

Make sure your SD card is formatted Fat 32 and is not faulty. Use the small Tasmania .img file
Use [Please Register or Login to download file] to see what is going on