Over-the-air (OTA) update
Delivering new firmware or software to a deployed device over its network connection instead of through physical access.
An OTA update lets a manufacturer fix bugs, patch vulnerabilities and add features on devices already in the field. The device downloads an image, verifies its signature, writes it to a spare slot in flash memory and reboots into it; a bootloader that can fall back to the previous image protects against a bad update bricking the unit.
Doing this safely is harder than it looks. Constrained devices may lack space for two images, cellular bandwidth costs money, and a flawed rollout can take an entire fleet offline at once. Staged deployment, delta updates and signed images are the usual answers. The mechanics are covered in Device management and OTA updates.
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