@macsbug Thanks for responding.
I have tried those two solutions and it didn't work:
- M5Burner - erase flash, burn UI-Flow
- M5Burner - erase flash, burn Core2FactorTest; I actually think it was this program that initially killed my display driver; I have two new m5Core2's and I wonder if this programs is installing the wrong display drivers for my new Core2.
- M5Burner - erase flash, burn M5Core2TouchPanelRecovery; I also tried this program but it was hard to use as I couldn't see the display menu; I used the power button to blindly select each of the two firmware drivers and to load them.