tangogps : updating tiles ?

[Xavier Cremaschi]

Hi folks,
I have been using tangogps since the beginning of my Openmoko life (july 
08), and now I've got lots of openstreetmap tiles stored on my microSD 
which cover useful areas for me.

Does anyone know how I can update my tiles to get the most up-to-date 
openstreetmap info ?
I don't care to re-dl all my tiles, but I don't want to download useless 
ones : my coverage is very specific, I have lots of tiles in order to 
cover cities on the coast (I zoomed and ask for a detail download of 
these cities), but almost nothing further in the land (not useful for 
me), so triggering a re-download of a huge rectangular area is NOT what 
I want.

Thanks in advance for your help,
Xavier.