[mkgmap-dev] Recent Garmin Firmware "cannot authenticate maps" when they are unicode

Sun Aug 27 09:31:56 BST 2017

Hi Franco,

 > I do not see any reason why GARMIN should only require UNICODE maps to
 > be signed, while LATIN1 maps can remain unsigned.

Signature is a protection for locked map. Garmin can't implement a 
protection, which would disable maps already sold, so the protection is 
triggered by a feature, which appears only in new maps.

 > I suspect that there is a flag in the file header, maybe a new and
 > undocumented one, that marks the file as "check for signature".

Code page is the flag. Independent flag in header would damage the whole 
idea of protection, if you could simply turn it off.

-- 
Best regards,
Andrzej