G'day testlelelala & r0cker
Test done, nice work. You should take a bow and have the rest of the day off, relax with a beer or 10 and charge them to Giomen.

test_original.img renamed gmapsupp.img has it's Map Name ZONA 1 read in StreetPilot 2610 Map Information display info screen following boot, but no details in Map Info of Menu and of course no detail map shown on screen, only base map as expected.

test.img as gmapsupp.img is read normally:

Spoiler: pic
SP2610 BA


Routed normally [as far as i can tell] on a 20.2 km simulated route Buenos Aires to San Fernando.
Congratulations.

PS: Did you make test_original.img 'Read Only' intentionally?