Hidden partition

Hard-disk based A5's (and at present that's all of them) contain a single hard disk with two partitions. Only one of these partitions is exposed in ordinary use, and only one is seen when the unit is connected as a USB device, under AVOS operation. To get to the hidden partition you'll need to boot the unit into recovery mode (hold down the volume up key when powering on) and then choose `Repair disk'. From there, you can get access to the whole disk. But even then you won't easily see the hidden partition, because it's not in the partition table.

On a Linux machine you can mount the hidden partition by specifying a particular offset on the raw disk device. For example, if it appears as /dev/sdc you can do

mount -o offset=XXXX /dev/sdc /mnt/tmp

Note that mounting a partition like /dev/sdc1 won't work. To find the offset you'll need to run fdisk on /dev/sdc (or whatever).

Disk /dev/sdc: 120.0 GB, 120031511040 bytes
x heads, y sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       14568     ...

The offset can got by multiplying the end of the first partition (14568 in this case) by the cylinder size (8225280). You can use the `bc' utility to do the math -- most desktop-style calculators will round very long numbers, which you really don't want here.