esp32s2: make flash: use the stub

Very long ago, this was apparently not supported in esptool yet, at
least when operating over USB CDC.  This now works just fine, and
our esp webtool relies on it as well.  It makes flashing faster,
too.

Author: jepler

ports/esp32s2/Makefile

@@ -338,10 +338,10 @@ $(BUILD)/firmware.uf2: $(BUILD)/circuitpython-firmware.bin
 	$(Q)$(PYTHON3) $(TOP)/tools/uf2/utils/uf2conv.py -f 0xbfdd4eee -b 0x0000 -c -o $@ $^
 
 flash: $(BUILD)/firmware.bin
-	esptool.py --chip esp32s2 -p $(PORT) --no-stub -b 460800 --before=default_reset --after=no_reset write_flash $(FLASH_FLAGS) 0x0000 $^
+	esptool.py --chip esp32s2 -p $(PORT) -b 460800 --before=default_reset --after=no_reset write_flash $(FLASH_FLAGS) 0x0000 $^
 
 flash-circuitpython-only: $(BUILD)/circuitpython-firmware.bin
-	esptool.py --chip esp32s2 -p $(PORT) --no-stub -b 460800 --before=default_reset --after=no_reset write_flash $(FLASH_FLAGS) 0x10000 $^
+	esptool.py --chip esp32s2 -p $(PORT) -b 460800 --before=default_reset --after=no_reset write_flash $(FLASH_FLAGS) 0x10000 $^
 
 include $(TOP)/py/mkrules.mk