fix: CMake build producing too large binaries

CMakeLists.txt

@@ -34,6 +34,10 @@ set(TINYUSB_DIR ${CMAKE_CURRENT_LIST_DIR}/lib/tinyusb/src)
 set(UF2CONV_PY ${CMAKE_CURRENT_LIST_DIR}/lib/uf2/utils/uf2conv.py)
 set(UF2_FAMILY_ID_BOOTLOADER 0xd663823c)
 
+if (NOT DEFINED CMAKE_BUILD_TYPE OR CMAKE_BUILD_TYPE STREQUAL "")
+  set(CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "Build type" FORCE)
+endif ()
+
 #-------------------
 # Bootloader
 #-------------------
@@ -131,7 +135,6 @@ if (CMAKE_BUILD_TYPE STREQUAL "Debug")
   target_include_directories(bootloader PUBLIC
     lib/SEGGER_RTT/RTT
     )
-
   target_compile_definitions(bootloader PUBLIC
     CFG_DEBUG
     SEGGER_RTT_MODE_DEFAULT=SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL
@@ -175,6 +178,7 @@ target_compile_options(bootloader PUBLIC
   )
 target_compile_definitions(bootloader PUBLIC
   SOFTDEVICE_PRESENT
+  CONFIG_GPIO_AS_PINRESET
   )
 
 if (TRACE_ETM STREQUAL "1")
@@ -333,4 +337,11 @@ add_custom_target(flash-mbr
 
 add_custom_target(flash-erase
   COMMAND ${NRFJPROG} -f nrf52 --eraseall
-  )
+  )
+
+# flash skip crc magic ( app valid = 0x0001, crc = 0x0000 )
+#add_custom_target(flash-skip-crc
+#  #COMMAND ${NRFJPROG} --memwr $(BOOT_SETTING_ADDR) --val 0x00000001 -f nrf52
+#  COMMAND ${NRFJPROG} --memwr 0xFF000 --val 0x00000001 -f nrf52
+#  #COMMAND ${NRFJPROG} --memwr 0x7F000 --val 0x00000001 -f nrf52
+#  )

README.md

@@ -114,14 +114,20 @@ You must have have a J-Link available to "unbrick" your device.
 
 ### Build:
 
-Firstly clone this repo with following commands
+Firstly clone this repo including its submodules with following command:
 
+```
+git clone --recurse-submodules https://github.com/adafruit/Adafruit_nRF52_Bootloader
+```
+
+For git versions before `2.13.0` you have to do that manually:
 ```
 git clone https://github.com/adafruit/Adafruit_nRF52_Bootloader
 cd Adafruit_nRF52_Bootloader
 git submodule update --init
 ```
 
+#### Build using `make`
 Then build it with `make BOARD={board} all`, for example:
 
 ```
@@ -137,6 +143,37 @@ Supported boards are: feather_nrf52840_express feather_nrf52840_express pca10056
 Makefile:90: *** BOARD not defined.  Stop
 ```
 
+#### Build using `cmake`
+
+Firstly initialize your build environment by passing your board to `cmake` via `-DBOARD={board}`:
+
+```bash
+mkdir build
+cd build
+cmake .. -DBOARD=feather_nrf52840_express 
+```
+
+And then build it with:
+
+```bash
+make
+```
+
+You can also use the generator of your choice. For example adding the `-GNinja` and then you can invoke `ninja build` instead of `make`.
+
+To list all supported targets, run:
+
+```bash
+cmake --build . --target help
+``` 
+
+To build individual targets, you can specify it directly with `make` or using `cmake --build`:
+
+```bash
+make bootloader
+cmake --build . --target bootloader
+```
+
 ### Flash
 
 To flash the bootloader (without softdevice/mbr) using JLink: