There is probably an easier way but this isn't too bad.
First you will need
BOOTICEx64.
Then you can remove your Kobo device's internal uSD card, from your device and plug it into the reader on your PC.
Open Bootice and check that the "Destination Disk" is your uSD card.
Select the "Parts Manage" button and "Backup Partition Table", to save the existing partition arrangement so it can be restored easily after you are done. [I save mine in the same folder I keep my backup image files.]
Then select the "KOBOeReader" partition and click on the "Set Accessible" button. It should move to the top of the list. Now backup the partition table again and give it a name like; "AuraHD_FAT1st.dpt"
Close and exit Bootice. Open Windows Explrer and you should now have the FAT32 partition mounted and you can modify its contents.
When you are done, you open Bootice and restore the original partition table, that you saved earlier. Your uSD card should now work in your Kobo device again, with the changes you made in effect.
So...Now all you need to do to "Mount" the uSD card with the FAT32 accessible (for updates, ect.), is to "Restore" the FAT1st version of the partition table. Make your changes and then restore using the backup of the original partition table.
[My AuraHD all of a sudden gave me a "Code 43 Device has a problem" message and my USB connection won't work. Trying to fix it has not been pleasant. The Code 43 error is keeping me from getting any of the USB connection options (Nickel's, your Start Menu's, or Sergey's) to work, therefor I needed another way to do upgrades. Windows normally can't read the kobo devices internal uSD card, but this way I can read and write to the FAT32 partition, and do my upgrades/modifications.
My AuraHD has a hatch that lets me remove the uSD card easily, so I can still make changes/upgrades even though I no longer have a working USB connection.]
Does anyone know of an easier way to mount the card in Win7 x64?
Luck;
Ken