Blog | G5 Cyber Security

USB Flash Drives: Firmware-Free Options?

TL;DR

Finding a USB flash drive *completely* without firmware is very difficult. Most rely on it for basic operation and wear levelling. However, some older or specialised drives come closer than others. We’ll look at what to consider and where to search.

Understanding the Problem

USB flash drives aren’t just simple memory chips. They need a controller chip to manage data storage, handle USB communication, and importantly, implement wear levelling (spreading writes across the memory to extend its life). This management is done by firmware – small programs embedded in the controller.

A drive without firmware would be very limited. It’d likely only work as a basic block storage device with no features like password protection, bad block handling or USB protocol quirks fixed.

Steps to Find (or Approximate) Firmware-Free Drives

  1. Understand What You Mean by ‘Firmware-Free’:
  • Research Older Drives:
  • Older USB 1.0 and early USB 2.0 drives are more likely to have simpler controllers with less complex firmware. Look for models from the late 90s/early 2000s.

  • Identify the Controller Chip:
  • Once you have a potential candidate, you need to find out what controller chip it uses. This is crucial.

    sudo usb-id -a
  • Teardown (Carefully!): If software identification fails, carefully open the drive casing and look for markings on the controller chip itself. Be very careful not to damage the drive.
  • Search for Controller Chip Documentation:
  • Once you know the controller chip model number (e.g., Alcor AU6973, SMI 2258), search online for datasheets and documentation.

  • Consider Open Source Firmware Projects (Advanced):
  • Some projects aim to provide open-source firmware replacements for certain USB controllers.

  • Test Thoroughly:
  • If you find a drive that seems promising, test it extensively.

    Drives to Investigate (as of Oct 2023 – availability varies)

    Important Warnings

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