Created with:
echo -n -e '\xff\xff\xff\xff' > empty.bin
./mkfw "MicroPython [LoBo] (20180726)" tile.raw 0 16 3145728 MicroPython build/MicroPython.bin 1 130 4194304 internalfs empty.bin
mv firmware.fw MicroPython.fw
Notes:
During testing, building with multiple threads failed. Only a single task build functioned correctly.
[update]
WiFi requires the phy_init_data.bin file to be flashed:
esptool.py write_flash 0x0f000 phy_init_data.bin