Documentation for flashing tbsense2 board using Makefile

[osresearch]

@EnJens - I received an email asking how to flash the tbsense2 board:

I found your EFR32MG micrpython repository on github. I purchased a TBSense2 board in hopes of running micropython on it. The normal make deploy did not work. Can you point me to something that will allow me to program the micropython image on it? I had assumed I could drop the firmware.bin file onto the USB file system it presents, but that does not work. Thanks in advance.

They followed up with success using another tool:

It would be nice to program it from the makefile. I was able to use the flash programmer tool in simplicity studio. Thanks for making the repository. Got it to boot micropython in the tbsense2 board.

[rlourette]

That was me. Once I used the simplicity studio flash loader (I used memory location 0x0 as the starting address) I was able to update the firmware using the drag and drop method with the firmware.bin file.