Very odd… I have another option if you’d like to continue trying? I’ve just “bricked” an MG24 here and tried and all worked OK.
It was mentioned by Seeed some time ago - check this post…
Basically there is a “recover” batch/script that can be run to try “recover” the device. It does help to have the D0 shorted to ground when reset or plugged in - then run the recover script.
If you get stuck - let me know.