I reply here as it seems to be similar issue:
ESP-01 powered by external supply. It ran for 1 month. Now blue LED is on and via terminal serie I can see:
Fatal exception (0):
epc1=0x4021058c, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00000000, depc=0x00000000
Fatal exception (0):
epc1=0x4021058c, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00000000, depc=0x00000000
Fatal exception (0):
I tried reflashing at 0x000000 and later on 0x40000080. No luck.
After flashing blank.bin, I get no further messages, but ESP is useless.
What else can I try until I get new ESP I have bought? (they may take 2 months!!!)
Or any Diagnostic to conclude that ESP is dead?
Many thanks!
Sergio.