New firmware release v1.17.2.b1 (Flash encryption support)

• esp32: Always use the DR specified during the join request (even for retries).
• esp32, lib: Fix deepsleep issues with LoRaWAN losing the channelmask and pending MAC commands.
• esp32/Makefile: If make SECURE=on then ENCRYPT=on is enabled by default.
• esp32: Added secure boot reflashable bootloader in make build-flow.
• esp32: Added Makefile flash encryption support, added comments in updater.c.
• esp32: Enabled Secure Boot, if make SECURE=on.
• esp32: Add argument to lte.attach() to specify the bands.
• esp32: Add option to setup the LTE carrier. Also allow for roaming registration.
• esp32: Move WLAN and LTE socket functions to a common module.
• esp32: Correct socket timeout implementation for WLAN.
• esp32: Change vTaskDelay for mp_hal_delay_ms where appropriate. This unlocks the GIL making possible better multi-threading.
• esp32: Use the correct IDF function for the Pin hold functionality.
• esp32: Revert to using the chip revision to determine the flash size. This works better with secure boot and flash encryption.
• esp32: Add WDT on boot API.
• esp32: Allow baud rates of up to 1000 Kbps for CAN bus.
• esp32: Make compliance script configurable to support all 4 regions and both activation methods.
• esp32: Update IDF libraries moving _gettimeofday to IRAM.
• esp32: Change LoRaWAN OTAA duty cycle from 15 to 10 seconds.
• esp32: Place hal_tick_ms function also in IRAM.
• esp32: Get latest binary.c file from MicroPython that fixes struct packing issues.
• lib/lora: Keep the data rate after a successful join accept.
• esp32: Fix the LoRa Rx messages time stamping. Thanks to @robert-hh.
• esp32: Run heartbeat on Core0, ensure pycom.heartbeat(False) is complete to avoid pycom.rgbled command to fail if used immediately after pycom.heartbeat(False)

For the instructions to enable flash encryptions and secure boot, please read here: https://github.com/pycom/pycom-micropython-sigfox#steps-for-using-secure-boot-and-flash-encryption.

Also, from the next release onwards we will no longer publish the appimg.bin as this is now identical to the regular firmware bin file. This is just as a heads-up so people can change their processes if anyone happens to use it.