Progressive (SOF2) JPEG decoder for memory-constrained systems. Decodes at 1/1, 1/2, 1/4 or 1/8 in a single forward pass with no seeking, storing only the low-frequency corner of each block that a reduced-scale IDCT will read. Storage still scales with the SOURCE image and not with the output, but with a much smaller constant than a general-purpose decoder: on a 12 MP 4:2:0 progressive file the peak is 23.0 / 8.9 / 3.6 MB at 1/2 / 1/4 / 1/8, against libjpeg-turbo's ~36 MB coefficient array at every scale. Size the budget from the frame header, not from the output you want; PSRAM is the assumption at megapixel sizes. Portable C99; I/O, row output and allocation are caller callbacks, so the large buffers can be pointed at external RAM while the hot working state stays internal.
ESP-IDF component for firmware updates via GitHub Releases. Polls the GitHub API for new releases, downloads the .bin asset, and flashes it. Supports partial HTTP download, OTA resumption across reboots, and anti-rollback (software semver check + hardware secure_version eFuse check).