You wrote: "6. Copied the gmapsupp.img to C:Garmin/ folder and renamed it gmapsupp.img. I'm thinking "renamed it gmapsupp.img" is a typo and you renamed it 'gmapprom.img' as required.

(Please see Edit below also)1.60GB total detail maps is getting big, I hope there's sufficient space left to fit your new East Coast map into rgn49 with MX in rgn10 already using 300MB of the shared space. If there's not sufficient available the worse case scenario would be that your current 2008 map will be erased by WU which will then be unable to fully transfer the large gmapprom.img to the device and if a partial transfer occurs it might 'brick' the device which will stick on loading maps or constantly re-start. Enough space might depend on whether 1.60GB is decimal or binary measurement because as decimal that's equivalent to about 1.49GB in binary. I have an unclear recollection that ~1.45GB (binary) is allocated for regions 10 and 49 to share out of the 2720's total flash size of ~1.75GB binary. Windows and Garmin do report sizes as binary usually. Safest option would be to check the space available. You can both save a copy of your current content of rgn49 and see the total size available utilizing the region dump function of GPSDaemon run in 'Full' mode. If you want to do that, first read the GPSDaemon thread from [Only registered and activated users can see links. ] in particular Post #34 for details about dumping regions of SP2720. Note that region numbers are treated as hexadecimal by GPSDaemon so decimal region 49 is '31' in hex and decimal 10 is '0A'. Of course it's your call whether you go to that trouble first or take the risk the US map will fit.

Certainly V2.57 is the latest version of WebUpdater. Make sure you also have the latest Garmin Devices Drivers installed too: [Only registered and activated users can see links. ].

The first command you wrote is what you need however you haven't copied it in full from Post #3. Whether running a command line or making a BAT file for it the path for WebUpdater folder needs be included so it starts with "C:\Garmin\WebUpdater". If using Command Prompt directly you may need to change directory first. As for the second one you wrote, the additional sample check written ("/unlock_check fid=XXXX pid=X") is unnecessary in your case because it asks WU to query the device whether unlock codes for the relevant map (identified by its FID & PID) are present. OSM are not locked maps. You can see a full list of the valid commands for WU in Post #8. Anyway, provided you have the Garmin folder directly in C drive and you have both the WebUpdater folder and the gmapprom.img inside that Garmin Folder the command "C:\Garmin\WebUpdater\WebUpdater.exe /upload_file rgn=49 path=C:\Garmin\gmapprom.img -autorun usb /i" (without quotes) is the one to use whether as a command line or in a BAT file. Be sure to run either as Administrator or it may not be recognized. A bat file is usually easiest for most ppl to use rather than opening a command line.

EDIT:I've just re-read your larger post more carefully. Maybe I've misunderstood and your East Cost file is only about 1GB (1,000MB) as said in your earlier Post #106 not 1.30GB as I've inferred from Post #107. Therefore if you've got only 1.30GB in total maps with US and MX they will fit comfortably and you can ignore the advice to check available space.