Download the file named "NV rgn16 dump&write Template - to 2.rar" from [Only registered and activated users can see links. ]. Extract the RAR file somewhere convenient to find Garmin\Updater\xxxx folders. Re-name the folder xxxx to 2436. In that folder is Update.txt, open it with Notepad and remove the entire second line, the one starting with 'xrgn'. Be sure there are no spaces, blank lines or carriage returns anywhere before saving it. What you should have is this:
Code:
Please Login or Register to see the links
1. Open the zumo firmware GCD file in [Only registered and activated users can see links. ] and save the boot.bin from first section, name it Ldr.bin - see behind spoiler below:
Spoiler:
[Only registered and activated users can see links. ]

2. Place the Ldr.bin file in the 2436 folder with the modified Update.txt.
3. Copy the Garmin folder into a CLEAN microSD card.
4. Ensure the zumo is completely OFF, not just in standby. Insert the card and turn on the device. If the battery is low or unreliable connect to a suitable external 5V power source to power it on (don't use a PC usb port to power it on).

The device should start to boot and then show "Loader", "Software Loading" or similar message on it's screen. Leave it until it finishes, it's finished when it re-boots normally.

Remove the card and you should have a new file named "16_backup.bin" in the root along with the Garmin folder.

Open 16_backup.bin in [Only registered and activated users can see links. ]. Behind next spoiler is "example only" from a nuvi 3590:
Spoiler:
[Only registered and activated users can see links. ]


Report what GIR_Editor shows for your zumo's logo as to both format and picture size. Then we can see if it's possible to modify your logo to BMW without complicated hex manipulation. If it's suitable we can proceed further.