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Scrubbing the memory of a device when deleting all device data

When you or a user deletes all BlackBerry® device data for a device when content protection is turned on, the device runs the memory scrub process to overwrite the device heap that is in RAM, the flash memory, and the files that a user saved on the device.

Scrubbing the device heap in RAM when deleting all evice data

To overwrite the BlackBerry® device heap that is in RAM for a device when content protection is turned on, the device changes the state of each bit four times. The memory scrub process for a device performs the following actions:
  1. writes 0x33 to each byte (0011 00112)
  2. writes all bytes to 0x00 (0000 00002)
  3. writes 0xCC to each byte (1100 11002)
  4. writes all bytes to 0x00 (0000 00002)
  5. writes 0x55 to each byte (0101 01012)
  6. writes all bytes to 0x00 (0000 00002)
  7. writes 0xAA to each byte (1010 10102)

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 00002). The memory scrub process deletes all blocks and changes all bytes to 0xFF (1111 11112).

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 00112)
  2. writes all bytes to 0xFF to each byte (1111 11112)
  3. writes 0xCC to each byte (0x1100 11002)
  4. writes all bytes to 0xFF (1111 11112)
  5. writes 0x55 to each byte (0x0101 01012)
  6. writes all bytes to 0xFF (1111 11112)
  7. writes 0xAA to each byte (0x1010 10102)
  8. writes all bytes to 0xFF (1111 11112)

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 01012)
  2. writes 0xAA to each byte (1010 10102)
  3. deletes all blocks, and changes all bytes to 0xFF (1111 11112) or 0x00 (0000 00002)

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