Its not dangerousto flash 37xx with original boot.bin from 34xx.
I flash Asian FW to EU 1300 with Asian boot.bin not EU.I take Asian FW and flash.
Asian FW work on EU nuvi that i tested with original asian FW (not change boot.bin) 2xx,2x5,2x5W,12xx,13xx,2xxx
All work like charm.