Nuvi 2465Sg/My / 2465TWN / 2455TWN / 2465TH all have hwid 1327.
I got 2465TH and flashed with 2465Sg/My & 23xxUS firmware by 4 methods. (We don't have 2465TH firmware till now.)

1). Flashed Nuvi2465TH with original 2465Sg/My (both boot&fw_all) directly
result :: Still be Thai region --> can not display Malaysia JCV.., (still show Thai JCV)

2). Flashed with modified 2465Sg/My firmware(both boot&fw_all) (changed hwid to other number)
Result :: hwid changed , can open Nuvi normally ., It seems work fine.., can not display Malaysia JCV.., (still show Thai JCV)
But boot = Fail (Inventory page) then I went back to 2465TH.

3). Flashed with 23xxUS firmware (whole file 23xxUSboot & 23xxUSfw_all) (changed hwid both boot&fw_all to 1327 same as 2465TH)
result :: can open Nuvi normally ., It seems work fine with US features But boot = Fail (Inventory page) then I went back to 2465TH.

4). Flashed with 23xxUS firmware (2465sgmy boot hwid1327 + 23xxUS fw_all overrided hwid to 1327)
result :: can open Nuvi normally ., It works fine with US features and all pass on inventory page.