Here is the step-by-step pragmatic approach for a typical 2020 Audi/BMW ECU (Bosch MG1CS011).
on bench with CAN tool or oscilloscope for crank/injector output ecu design pinout patched
Cause: You interrupted power during the checksum patch write. Fix: Use a boot pinout to force the ECU into "Rescue Mode." With the correct 4-pin JTAG pinout (TDI, TDO, TMS, TCK), you can re-flush the original bootloader. Here is the step-by-step pragmatic approach for a