Reflash

Reflash is the process of rewriting the firmware stored in a device’s flash memory. It typically involves replacing an existing firmware image with a new or corrected one, and is distinct from the initial manufacturing flash. Reflashing is performed to apply updates, fix firmware corruption, recover a malfunctioning device, or install an alternative or custom firmware in some cases.

Reflashing is common in a wide range of devices, including routers, cameras, smartphones, and personal computers (for components such as BIOS/UEFI). The procedure usually requires putting the device into a special mode—such as a bootloader, recovery, or DFU mode—and establishing a connection via USB, JTAG, or a serial interface. Tools may be vendor-provided or community-developed, and the process relies on a firmware image file, often with signature or integrity checks.

Typical reflashing steps involve obtaining the correct firmware image for the device and version, verifying its integrity, entering the appropriate reflashing mode, writing the image to flash memory, and then rebooting to complete the process. Some devices include additional safeguards, such as cryptographic signing, bootloader locks, or rollback protections that can affect reflashing.

Risks and cautions include the potential to render a device inoperable if the flash operation is interrupted or an incompatible image is used. Incorrectly reflashing can brick hardware, void warranties, or result in data loss. Users should ensure they have the correct model and revision, follow official instructions or trusted guides, and maintain power stability during the process. Reflashing may be used to restore functionality, apply security updates, or replace compromised firmware, and is a common maintenance task in embedded systems and consumer electronics.