esp8266: Provide sensible default ESP_SDK; deploy 2 the images together.

esp8266/Makefile

@@ -6,12 +6,9 @@ QSTR_DEFS = qstrdefsport.h #$(BUILD)/pins_qstr.h
 # include py core make definitions
 include ../py/py.mk
 
-ifeq ($(ESP_SDK),)
-$(error ESP_SDK must be set)
-endif
-
 PORT = /dev/ttyACM0
 CROSS_COMPILE = xtensa-lx106-elf-
+ESP_SDK = $(shell $(CC) -print-sysroot)/..
 
 INC =  -I.
 INC += -I$(PY_SRC)
@@ -73,9 +70,8 @@ all: $(BUILD)/firmware-combined.bin
 
 deploy: $(BUILD)/firmware-combined.bin
 	$(ECHO) "Writing $< to the board"
-	$(Q)esptool.py --port $(PORT) write_flash 0 $<
-	#$(Q)esptool.py --port $(PORT) write_flash 0 $(BUILD)/firmware.elf-0x00000.bin
-	#$(Q)esptool.py --port $(PORT) write_flash 0x10000 $(BUILD)/firmware.elf-0x10000.bin
+	#$(Q)esptool.py --port $(PORT) write_flash 0 $<
+	$(Q)esptool.py --port $(PORT) write_flash 0 $(BUILD)/firmware.elf-0x00000.bin 0x10000 $(BUILD)/firmware.elf-0x10000.bin
 
 $(BUILD)/firmware-combined.bin: $(BUILD)/firmware.elf
 	$(ECHO) "Create $@"