Fix esp8266 bootloader building and add diagnostic tools (#2734)

This PR focuses on an issue discovered in #2727 when attempting to update the esp8266 boot partition from code during a firmware update.
It was discovered that doing this renders the device unbootable because the boot sector header information is incorrect.

This is because the required `SPI_SIZE`, `SPI_MODE` and `SPI_FREQ` values were never passed to the rboot makefile when building.
When flashing the boot partition normally, these parameters get passed to esptool, which modifies the provided boot image.
I wasn't aware until now that it did this!

**Build rboot as variant**

The solution to the main problem is to build rboot as a variant - see https://sming.readthedocs.io/en/latest/_inc/Sming/building.html#library-variants.

The location of the bootloader firmware (in `out/Esp8266/debug/firmware/rboot.bin`) is unchanged,
but is overwritten by the appropriate variant after every build.

This should ensure consistency with selected settings.

**Remove RBOOT_INTEGRATION**

As we've forked rboot some time ago this isn't necessary, so we can simplify the code a bit.

**Update esptool to v4.6.2 (from v4.4)**

Version 4.7 has issues with earlier python versions and breaks with IDF 4.4/4.3.

**Add `bootinfo` build target**

Adds `make bootinfo` for esp architectures which shows details of the boot partition,
including header fields so we can check it's correct.

**Add `esptool` build target**

Makes for easier access to esptool.

Sming/Arch/Esp32/app.mk

@@ -38,3 +38,11 @@ endif
 
 $(TARGET_BIN): $(TARGET_OUT)
 	$(Q) $(ESPTOOL_CMDLINE) elf2image --min-rev $(CHIP_REV_MIN) --elf-sha256-offset 0xb0 $(ESPTOOL_EXTRA_ARGS) $(flashimageoptions) -o $@ $<
+
+
+##@Flashing
+
+.PHONY: bootinfo
+bootinfo: $(FLASH_BOOT_LOADER) ##Show bootloader information
+	$(info $(FLASH_BOOT_LOADER):)
+	$(Q) $(ESPTOOL_CMDLINE) image_info -v2 $(FLASH_BOOT_LOADER)

Sming/Components/esptool/component.mk

@@ -86,3 +86,11 @@ endef
 define EraseFlash
 	$(call ESPTOOL_EXECUTE,erase_flash)
 endef
+
+
+##@Flashing
+
+.PHONY: esptool
+esptool: ##Pass options to esptool, e.g. `make esptool -- --help` or `make esptool image_info` 
+	$(Q) $(ESPTOOL_CMDLINE) $(filter-out $@,$(MAKECMDGOALS))
+

Sming/Components/rboot/component.mk

@@ -30,6 +30,17 @@ endif
 
 # => APP
 
+# Build bootloader variant based on these variable values
+RBOOT_VARS := \
+	PARTITION_TABLE_OFFSET \
+	RBOOT_RTC_ENABLED \
+	RBOOT_GPIO_ENABLED \
+	RBOOT_GPIO_SKIP_ENABLED \
+	RBOOT_SILENT \
+	SPI_SPEED \
+	SPI_MODE \
+	SPI_SIZE
+
 # rBoot options
 CONFIG_VARS				+= RBOOT_RTC_ENABLED RBOOT_GPIO_ENABLED RBOOT_GPIO_SKIP_ENABLED
 RBOOT_RTC_ENABLED		?= 0
@@ -102,12 +113,6 @@ RBOOT_ROM_1_BIN			:= $(FW_BASE)/$(RBOOT_ROM_1).bin
 
 
 COMPONENT_APPCODE		:= rboot/appcode
-APP_CFLAGS				+= -DRBOOT_INTEGRATION
-
-# these are exported for use by the rBoot Makefile
-export RBOOT_BUILD_BASE	:= $(abspath $(COMPONENT_BUILD_DIR))
-export RBOOT_FW_BASE	:= $(abspath $(FW_BASE))
-export ESPTOOL2
 
 # multiple roms per 1mb block?
 ifeq ($(RBOOT_TWO_ROMS),1)
@@ -143,12 +148,20 @@ ifdef RBOOT_EMULATION
 FLASH_BOOT_CHUNKS		= 0x00000=$(BLANK_BIN)
 FLASH_RBOOT_ERASE_CONFIG_CHUNKS	:= 0x01000=$(BLANK_BIN)
 else
-export RBOOT_ROM0_ADDR
-export RBOOT_ROM1_ADDR
+export ESPTOOL2
+export $(RBOOT_VARS)
+RBOOT_VARSTR := $(foreach v,$(RBOOT_VARS),$v=$($v))
+RBOOT_HASH := $(call CalculateVariantHash,RBOOT_VARSTR)
+export RBOOT_BUILD_BASE := $(COMPONENT_BUILD_BASE)/$(RBOOT_HASH)
+RBOOT_VAR_BIN			:= $(RBOOT_BUILD_BASE)/rboot.bin
 RBOOT_BIN				:= $(FW_BASE)/rboot.bin
-CUSTOM_TARGETS			+= $(RBOOT_BIN)
-$(RBOOT_BIN):
-	$(Q) $(MAKE) -C $(RBOOT_DIR)/rboot PARTITION_TABLE_OFFSET=$(PARTITION_TABLE_OFFSET) $(RBOOT_CFLAGS)
+CUSTOM_TARGETS			+= build_rboot
+$(RBOOT_VAR_BIN): $(ESPTOOL2)
+	$(Q) $(MAKE) -C $(RBOOT_DIR)/rboot $(RBOOT_CFLAGS)
+
+.PHONY: build_rboot
+build_rboot: $(RBOOT_VAR_BIN)
+	cp $(RBOOT_VAR_BIN) $(RBOOT_BIN)
 
 EXTRA_LDFLAGS			:= -u Cache_Read_Enable_New
 
@@ -207,4 +220,13 @@ $(RBOOT_ROM_1_BIN): $(TARGET_OUT_1)
 
 endif
 
+
+##@Flashing
+
+.PHONY: bootinfo
+bootinfo: ##Show bootloader information
+	$(info $(RBOOT_BIN):)
+	$(Q) $(ESPTOOL_CMDLINE) image_info -v2 $(RBOOT_BIN)
+
+
 endif # RBOOT_EMULATION