Dont panic. In most cases the ECU isnt actually bricked - the flash just didnt complete properly. Try these steps: 1) Disconnect the battery for 30 minutes. 2) Reconnect and try to flash the stock file back. 3) If the car cranks but wont start, the ECU is alive - it just has a bad map. 4) If theres zero response (no dash lights, no crank), check the OBD fuse first.\n\nWhat tool did you use for flashing? And what engine/ECU type?
This happened to me once with a Bosch MEVD17.2 ECU. The issue was the battery voltage dropped during flashing. Always use a battery charger during ECU flashing - the process draws a lot of power and if voltage drops below 12V mid-flash, it can corrupt the data. I recovered mine by bench-flashing with a BDM adapter.
