Nuvi 750 and SD card format question

Both the Nuvi and the SD card are formatted as Fat32. You should have no problems and don't need to update the firmware if your happy with 4.10

Can't answer your question about SDHC cards and earlier firmware but I can recommend that you use a newer firmware than 4.10.

Here's a link to the nuvi 750 changelog history page:
http://www8.garmin.com/support/download_details.jsp?id=3811

Here are links to firmware updates between 4.10 and 4.90 (4.30, 4.40, 4.50 & 4.70 were never publicly released)

v4.20:
http://www.garmin.com/software/nuvi7xx_regionfileonly__420.g...
v4.60:
http://www.garmin.com/software/nuvi7xx_regionfileonly__460.g...
v4.80:
http://www.garmin.com/software/nuvi7xx_regionfileonly__480.g...

I would recommend v4.80

To update the unit using the file download from the above links, connect the nuvi to the PC via USB, allow it to be detected, then drag the downloaded file to your WebUpdater icon. On the next nuvi power-cycle, the firmware will be updated.

To keep 4.80 on the unit and prevent a forced update to the newest version, delete GUPDATE.GCD from the x:\Garmin folder immediately after running WebUpdater to check for additional updates or after using myDashboard to do any updates. *The file needs to be deleted before a power-cycle.* Reconnecting the nuvi to the PC to delete the file is fine since this will not initiate the firmware update if applicable.

The actual firmware update is performed by GUPDATE.GCD on a power-cycle if the nuvi sees that the firmware version contained in GUPDATE.GCD is newer than what is currently on the unit.

Here's a repost of of mine on how to keep the unit at a certain firmware version, even while performing a map update or during the registration process as Garmin always forces an update (if one is available) on the unit if it is not current. This may be way more info than you asked for or need but I thought I'd include it nonetheless for completeness...

Repost

Right-click on the file named GarminDevice.xml on the nuvi drive located in x:/Garmin and select "Open With" and choose Notepad. Look for the following line approx 6 lines down from the top:

< SoftwareVersion >320< /SoftwareVersion >

The current software version on the unit is listed here. The example above is 320 (version 3.20) and coincides with the actual version flashed to the unit. Change the 320 (or whatever other version number it is) to 420 or to whatever the current available Garmin version number is. Make no other changes.

*Note that I had to add spaces in the example line above so the forum would not interpret the line as valid html code. Don't add the spaces that I added above.

After doing so, save the file (file/save). Don't unplug or power off the unit...keep it connected to the PC. Run the registration process again which should now let you register the unit. After doing so, be sure and delete GUPDATE.GCD if it gets installed on the nuvi again somewhere in the process.

Don't worry if you somehow mess up on the file editing as this file is regenerated at every nuvi power cycle.

From here on afterwards, you will have to delete GUPDATE.GCD from the nuvi every time after running WebUpdater since each time you do, it will find the newest update and reinstall GUPDATE.GCD again since you will still have an older version on the unit.

Editing the GarminDevice.xml file simply temporarily fools WebUpdater and/or the registration process into thinking that the most current software verison is already installed on the unit. After the nuvi is power cycled & GarminDevice.xml is regenerated, the software version listed in the file will again list the
older version that is currently on the unit.

You will also again have to re-edit the GarminDevice.xml file just before before installing the map update to avoid the forced firmware update.

This is great information.

I have a 750 with firmware 4.9 and have had no problems with it. I use an SDHC 8GB card for my MP3's. Still working on filling it up. I've had this card for awhile but not sure what other firmwares I've used with it.