Data Recovery for USB Memory Sticks and Cards
Cheap, portable and with rapidly increasing storage capacity. Flash memory is becoming the media of choice for transferring data between computers. For information on memory cards and memory sticks (pen drives), and other Flash NAND-based storage please see our introductory guide, “How do SSDs and Memory Sticks work?”.
There are many types of flash memory media including SD Cards ( Standard, Mini & Micro), Sony Memory Stick, MMC, Compact Flash I & II, XD, PC Card, and USB pen drives.
Typical failures of memory sticks and cards:
- Physically damaged devices
- Deleted files
- Formatted drives
- Bent, snapped or damaged USB connectors
- Failed controller / processor chip
- Device not recognised
- Bad blocks
Pen drives have no moving parts, and consequently are more robust that hard disk drives. However, frequently seen failures include physical damage to the printed circuit board near the USB connector. For summary information on Flash NAND-based storage media, please read ‘Flash NAND media – an introduction.’
Methods used for recovery
Specialist equipment is required for performing ‘chip-off’ data recovery techniques. These are performed when the controller / processor chip on the memory stick or card has failed. The flash NAND chips are removed by use of hot-air or infrared heat. The NAND chips are cleaned and then read directly. The raw data ‘dump’ is extracted from the NAND chip. It is then transformed into usable data in the form of files. The transformations required, including error control checking (ECC), and XOR, are becoming increasingly complex on modern devices. Consequently the time it takes to make a successful recovery on a high capacity memory stick / card has also increased. For devices of a capacity of 32GB or greater, the time it takes to read the chips can be many hours, even one or two days once ECC is established and a re-read is required. Only once a good read-out from the NAND is acquired then the other transformations can take place.
What happens if recovery is not possible?
Cheadle DATA Recovery Ltd will always be realistic in advance with customers about the work required whilst also being open about the recovery process. On occasions, the model of memory stick / card processor is not supported by the data recovery equipment that we, or any other company, uses. This means that it will not be possible to recover the data. However, each year there are updates released for the data recovery equipment, and additional generations of flash NAND processors are added. This means that whilst it might not be possible to recover your data at the time, it might be in the future. In these cases, we will note the customer’s email address, and when support is provided for their memory stick an email shall be sent updating them, and whether they wish for a further attempt to be made on the failed device.
You can check to see whether the model of processor on your memory stick / card is supported by viewing the website of the manufacturer of the data recovery equipment. Visit AceLabs Flash archive and the SoftCenter Library.