clemens@secrets:~/Devel/ESP8266/genesys$ make stack
0x402010cf: __wrap_realloc at ??:?
0x40104c5c: lmacTxFrame at ??:?
0x4020ffcc: yield at ??:?
0x4020f76d: UpdaterClass::_writeBuffer() at ??:?
0x4020f81f: UpdaterClass::write(unsigned char*, unsigned int) at ??:?
0x402102da: String::String(char const*) at ??:?
0x4020de24: handle_update_progress_cb(AsyncWebServerRequest*, String, unsigned int, unsigned char*, unsigned int, bool) at http.cpp:?
write
and _writeBuffer
Updater.runAsync(true/false);
to switch the modes