There are two principal methods when dealing with cell phone data retrieval and flash recoveries. By interrogating the NAND memory chip, both these techniques give data recovery engineers access to a low-level picture of the data, though they are both very different.
When it comes to hard disk drives that they tend to use a standard approach to storing information, meaning that data retrieval tools can be generic.
The first technique is the chip-off strategy. This technique requires de-soldering the memory chip in the circuitry. So as to remove the chip in the device without causing any harm it requires precision ability under a microscope as making any very small mistakes risks losing all of the data permanently. After the processor is removed it may be read with info extractors. NAND chips are usually a lot easier to read than other kinds of chip and are normally what SD cards and iPhones use. This is a result of the memory structure and pin configuration being standardised. The hooks are on the exterior meaning there’s absolutely no need to reconstruct the connectors. Other common kinds of chip like the BGA have multiple connectors on the bottom that are directly soldered to the motherboard with a large number of unique configurations so are a lot more challenging to remove.
The second technique is JTAG that doesn’t require removal of the processor. A data recovery engineer can occasionally access the memory via the JTAG ports. This is a much more lengthy process and doesn’t damage the media. This means it can be held in a working state that’s sometimes a vital requirement in forensic investigations. A downside of this technique is that it’s not always as effective and may be a riskier option.
Both approaches will produce a low-level image that’s then ‘deciphered’ and the user’s data can be reconstructed. The two chip-off and JTAG technology is growing and getting far more dependable meaning that the success rates of data retrieval from cellular phones is almost as great as that of hard disk drives.