thanks to the gdb stub from the guys at Cesanta, i can now halt the ESP on exception, attach the debugger and inspect memory and stack :) extremely helpful.
too bad their code is GPLv2, so i can only use it locally...
File f = open("/spi/config.txt", "r");
File f = SPIFFS.open("/config.txt", "r");
FS.openDir, etc. or just leave freestanding functions to do that