If your TinyHawk is only showing a red LED indicator, try re-flashing the original firmware using the Boot button, which is on the top side of the AIO board. (Not the Bind button, which on the bottom/battery side.) The Boot button may be a bit tricky to get to unless you remove the four screws holding the battery mount and AIO board. 

Once you can access the Boot button, you will need to hold it down (use a non-metallic tool to avoid shorting out the electronics) while plugging in the USB cable (make sure it is a data cable, not just a power/charging cable). It is normal that the board's LED's will NOT light up at this point. Betaflight Configurator should now show "DFU" where you usually see your connected COM Port.

After re-flashing the firmware via the Boot button, please re-apply the stock CLI.


Optional (as needed):

When using the Boot button to get into DFU/flashing mode, you may need to try enabling "No reboot sequence". Then click the "Flash Firmware" button once the USB cable is connected. Optionally, you may try "Flash on connect", such that you would not need to click the "Flash Firmware" button manually. There may be a bit of trial and error, but the firmware should ultimately flash.