In reply to @chronos.vitaqua "Damn, what formats for": mostly iot/router
firmware images and proprietary network protocols and stuff like that. Most
recently I reverse engineered a router's bootloader which had a separate
maintenance mode for flashing new firmware in case the whole device goes belly
up and you can't even reach the normal FW upload page. The problem was that the
maintenance mode used a totally custom firmware upload protocol which I had to
figure out from scratch on the packet layer - how to segment the data, how to
determine which partition to write to, how the checksum was calculated etc