Thanks Duke!
I will try it when free
So far !!!!!!!
I've been following this thread with interest and decided to post my findings, although my unit is the HD550 on firmware 1.021
I purchased a 64gb card which was already formatted to FAT32 but decided to format it again anyway, it then decided it was a 32gb card so I formatted it with HPUSB disk which doesn't seem to offer a cluster size adjustment, following this the card was a 64gb again. Anyway I got tired formatting it at 2hrs a time and just put it in the unit, the 'initialising SD card' message came, followed by the 'safe driving' message and its been working happily ever since.
So I didn't have to pre-install anything on the card, just freshly format it and away.
Maybe the latest firmware has addressed any previous problems.
I have no idea how to check if this card is genuine or not, its a Sandisk, I bought it from a supplier I used before and have had no problems with, I would welcome any help as to check its authenticity.
My camera said nothing about formatting the card, it just went through its normal cycle of initialising sd card then safe driving messages. When I pulled the card it shows as 59gb on the pc and having been run for a day in the camera and is only about half full of video. I drive between 9-11 hours per day. If I remove the card at the end of a day, with the 32gb the recording from the start of the day have been written over, but the 64gb card still has recordings from yesterday on it. A lot of the comments on this thread are about the HD500, mine is the HD550.
Maybe its something to do with the latest firmware?
Does the DR400G (first version) support 64GB SDXC card?
Also, by formatting the 64gb to fat32, does this reduce the capacity?