docs: Update firmware flashing guide

Signed-off-by: Ajay Bhargav <[email protected]>

Author: ajaybhargav

docs/_static/arduino-ide-flash-menu.png

@@ -1,8 +1,66 @@
 Firmware Flashing Guide
 =======================
 
+Core and application firmware flashing is supported on both PlatformIO and Arduino IDE.
+
 Flashing Application firmware
 -----------------------------
 
-Core Firmware Reflash
----------------------
+Upload Application via PlatformIO
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Click on the upload icon in bottom toolbar as shown in picture
+
+.. image:: ../_static/platformio-ide-code-build.png
+
+Upload Application via Arduino
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Directly click on upload button in toolbar as shown
+
+.. image:: ../_static/arduino-ide-flash-upload.png
+
+Alternatively from Menu bar, go to Sketch -> Upload
+
+.. image:: ../_static/arduino-ide-flash-menu.png
+
+
+Core Firmware Re-flash
+----------------------
+
+Currently core re-flashing of GSM devices is possible and it's only supported on windows platform due to vendor limitation.
+
+Flashing Core via PlatformIO
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+1. Open project tasks by clicking PlatformIO icon from left sidebar
+2. Under custom tasks, click "Reflash Core Firmware"
+
+.. image:: ../_static/platformio-ide-flash-core.png
+
+3. Core flashing will start, check progress in terminal windows
+
+.. image:: ../_static/platformio-ide-flash-core-progress.png
+
+Flashing Core via Arduino
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+1. Select Programmer from Tools -> Programmer -> Logicrom Core Flasher (MT2503/MT6261)
+
+.. image:: ../_static/arduino-ide-select-logicrom-flasher.png
+
+2. Select device COM port under Tools -> Port
+
+.. image:: ../_static/arduino-ide-select-logicrom-flasher-port.png
+
+3. Click Tools -> Burn Bootloader to start flashing. Check flash progress in the output console
+
+.. image:: ../_static/arduino-ide-logicrom-flasher-progress.png
+
+Flashing Issues
+---------------
+
+If you face any problem during application or core flashing, Please open new issue here:
+
+https://github.com/waybyte/platform-logicrom/issues
+