Description
As pointed out by @sfe-SparkFro there might be users who want to use this tool but not with one of the supported SparkFun boards. To make this more intuitive we could possibly add selectable pictures for "generic ESP32", "generic RP2", and "generic MIMXRT".
When users select one of these new default board options, only the "custom firmware" firmware option will be populated.
We could also make the auto-detect default to the correct new "default" board selection if the mpremote platform check doesn't match one of the supported boards but is for one of these platforms (ESP32, RP2, or MIMXRT).
When a default board option is selected for ESP32, we should maybe display a warning notification to the user saying something along the lines of "Flashing will be performed by using esptool and flashing to address xxxxx. If your platform uses a different method for firmware updates, it is not supported. Check micropython.org/download/REPLACE_WITH_YOUR_BOARD_NAME/ for flashing instructions". Only thinking of this because we ran into an arduino esp32 board that has a different bootloader and corresponding tool for flashing firmware.