For US/EU 37xx series, the correct reference for the <model> is "006-D1101-00" (so HWID 1101). Your quoted "006-D0397-00" is for the <update file>.

Use the ramloader (boot.bin) for V5.10 after ensuring your device's XML has this towards the beginning:
Code:
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1:/ is the path to the media card in nuvi 37xx HWID 1101 series and its non-vol region is 41. Therefore use:
rrgn,41,1:/41.bin
reboot