If you are currently looking at the "Verified: Failed" screen, follow this drill. Do not cycle the ignition yet.
What Is a Checksum Error? Causes, Types and Fixes - Nadcab Labs checksum error writing buffer kess v2 verified
At this point, the verified professional move is to use a dedicated programmer (like CMD Flash or PCM Flash) to force a low-level write, or send the ECU to a specialist for a JTAG recovery. If you are currently looking at the "Verified: