When the update is completed, the CP73 screen should report the version it installed and “Completed. Please turn off.” or it reports “N/G” indicating the updater failed... No Good.
You are reporting that your CP73 screen is reporting “Checksum error” — is that exactly what is happening?
You do not see “Completed. Please turn off.”
You do not see “N/G”?
Your CP73 screen reads “Checksum error”
Forgive me for these questions but that’s not a response it should be showing under the updater routine.