An ESPHome development-build fault can leave some ESP8266 devices unable to accept another wireless update or save settings to flash. It affects configurations that override the board’s memory layout with a larger size, including the described Athom configuration.
J. Nick Koston makes the new native build system write a matching size into the firmware header. A device already running the broken development image needs one serial reinstallation; a device still using firmware built with PlatformIO can update wirelessly to a corrected build. Ordinary board layouts are unchanged.