User guide

3. writes 0xCC to each byte (1100 1100
2
)
4. writes all bytes to 0x00 (0000 0000
2
)
5. writes 0x55 to each byte (0101 0101
2
)
6. writes all bytes to 0x00 (0000 0000
2
)
7. writes 0xAA to each byte (1010 1010
2
)
Scrubbing the flash memory on a device when deleting
all device data
For a BlackBerry device that is running BlackBerry Device Software version 4.6 or later and that has content protection
turned on, the memory scrub process overwrites the NAND flash memory by writing a single character before it deletes the
data. The memory scrub process writes 0x00 to each byte (0000 0000
2
). The memory scrub process deletes all blocks and
changes all bytes to 0xFF (1111 1111
2
).
For a device that is running a version of BlackBerry Device Software that is earlier than version 4.6 and that has content
protection turned on, the memory scrub process overwrites the NOR flash memory by changing the state of each bit four
times. The memory scrub process performs the following actions:
1. writes 0x33 to each byte (0011 0011
2
)
2. writes all bytes to 0xFF to each byte (1111 1111
2
)
3. writes 0xCC to each byte (0x1100 1100
2
)
4. writes all bytes to 0xFF (1111 1111
2
)
5. writes 0x55 to each byte (0x0101 0101
2
)
6. writes all bytes to 0xFF (1111 1111
2
)
7. writes 0xAA to each byte (0x1010 1010
2
)
8. writes all bytes to 0xFF (1111 1111
2
)
Scrubbing the user files on a device when deleting all
device data
If a BlackBerry device supports a partition of flash memory to store files that a user saved to the on-board device memory
and you or a user turned on content protection, the memory scrub process overwrites that section of the device memory by
writing a single character before the memory scrub process deletes the data. The memory scrub process performs the
following actions:
1. writes 0x55 to each byte (0101 0101
2
)
2. writes 0xAA to each byte (1010 1010
2
)
3. deletes all blocks, and changes all bytes to 0xFF (1111 1111
2
) or 0x00 (0000 0000
2
)
Security Technical Overview Device storage space
53