I have a new M5Stack Core2 that was working perfectly on arrival with the pre-installed factory test program.
I used M5Burner to install UIFlow_Core2 and that worked. I was able to use flow.m5stack.com to send simple programs to the device and everything I tried worked.
I then used M5Burner to re-install Core2FactoryTest and the burn appeared to work but the device then entered an infinite boot loop, reporting (via the serial monitor):
ets Jul 29 2019 12:21:46
rst:0xc (SW_CPU_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
mode:DIO, clock div:1
ho 0 tail 12 room 4
Guru Meditation Error: Core 1 panic'ed (IllegalInstruction). Exception was unhandled.
Memory dump at 0x400f2f20: 443a20c2 0d0e272a 02a8130c
I've tried re-installing UIFlow_Core2 and Core2FactoryTest several times. Each time, UIFlow_Core2 works perfectly and Core2FactoryTest fails as described.
I've also tried several other programs via M5Burner: some work and some fail to boot, some with "IllegalInstruction", some with "InstrFetchProhibited".
Any ideas? I suspect a hardware fault but can't reconcile that possibility with the fact that some programs work.