There are two ways to load the MicroPython firmware to the device:
The MicroPython firmware or the UF2 bootstrap loader can be loaded to the MIMXRT development boards in various ways. The most convenient one is using the built-in support MCU. When a PC is connected to the debug USB port, a drive icon will appear. Firmware can be uploaded to the board by copying it to this drive. The copy and flashing will take a few moments. At the end of the upload, the drive icon will disappear and reappear again. Then the reset button has to be pushed, which starts the MicroPython firmware.
Depending on the power jumper settings, both the debug USB and OTG USB port have to be powered during firmware upload.
You may as well load the firmware using the JLink port or openSDA interface with the appropriate tools. For more options, consult the user guide of the board.
When using the UF2 bootloader, the OTG USB port will be used. Once the UF2 bootloader is installed, it has to be started to upload MicroPython.The methods to start the bootloader are:
If there is no valid Firmware on the device, the bootloader will start automatically. Once it's started, a drive ICON will appear. The MicroPython firmware file with .uf2 extension must then be copied to that drive. When the file is copied and MicroPython is installed, the drive disappears and MicroPython starts.