Old SD cards are small, cheap, and surprisingly versatile — when repurposed with care they make excellent bootable rescue drives, multiboot toolkits, media sticks, encrypted key carriers, and compact test platforms — but getting dependable results means understanding formats, performance limits, risk vectors, and a short verification workflow before you rely on a card in the field.
Background / Overview
SD and microSD cards are everywhere: cameras, phones, action cams, single‑board computers...