Quote Originally Posted by Giomen View Post
Small addition:

Extraordinary majority of map what distribute in the img format do not have personal data! Especially if file have a flag - Ms 0

In any case no problem to check that. You can parse unlock code from img and you see unit ID=1 or the same as in any other version of this map. Only if you received map generated specially for you by mapsource you have personal data in it.
For experts, these may be stupid questions.
Since I am not an expert, I post them anyway:

1. What is the Ms flag used for?

2. What are the possible Ms flag values, and what do these values indicate or determine?

3. Why do some IMG files contain unlock codes (i.e., why are the unlock codes in the IMG file, not just in a separate .unl file)?

4. Is a separate .unl file required, even if an IMG file contains an unlock code?

5. If a separate .unl file is still required, do the unlock codes in the IMG file and in the separate .unl file have to be identical (or can they be different, yet both valid unlock codes for a given GPS unit or SD card)?

6. What software product puts the unlock codes in the IMG files, and when (or under what conditions) does it do so?

7. Why and when (or under what conditions) does an IMG file contain more than one unlock code?

In other words: I want to learn more, so that I can better understand what is going on (and avoid posting stupid questions in the future).

Quote Originally Posted by catymag View Post
IMHO:
1-Remove personal data with Hex Editor, posters should do it always and Hex Editor doesnt modify the map header.
2-Always download original locked maps and unlock by yourself.
2-Unlock with gimgunlock: it doesnt modify neither the header nor remove the product code in header.
I agree (using a hex editor is a good option, because it leaves the rest of the file unmodified).
However, some less experienced users may not feel comfortable with using a hex editor.

Downloading original locked maps (and unlocking by yourself) certainly is best (I think it would be great if more original locked maps were made available here). That way it is possible to keep the original download, and to start over if something does not work out (or if Garmin decides to change something in the future).