Curious. Please describe exactly the process.

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.

I made an new attempt.
While "Updating Wave 22/22", between 20-30%, the screen reports "Check Sum error!".
I wonder if the update files may have been corrupted somehow, but I downloaded them twice...

Perhaps your thumb drive has a corrupted sector.
Your instrument reports it is updated... already.

Problem solved ! The only change I did was to copy the file 8S89OS_.PGM from a PC to the usb key (was copied from Mac).
I got "Completed. Please turn off."

I suspect a usb key formated on CP (File Utility/Format) may causes some quirks on Mac... may be...

Hello !
Same problem with my CP73, i did the opération many times, but it shows the same « checksum error » message every time..
Now i can’t use my keyboard...
what can i do ?
Thank you !

Hi, me too: have same problem but with CP88 !!
Now no sound out
Can you help me?
Thanks

Take your time, follow the instructions. A Checksum error means the file you are using does not check out, it is the wrong size.

The updater file must be downloaded, then unzipped on your computer, copy the .PGM File to your usb stick’s root directory (not in a folder). Use a USB stick you use to save and load files to your instrument.

What version is your instrument currently displaying?

Ok the problem was the usb pendrive that wasn't formatted by the cp88
changing pendrive & FORMATTING IT whit PIANO,
copy ONLY the file named 8S89OS_.PGM (or 8S89OS viewed) in the root
then update it

Hi,
I had the same problem: "checksum error".
I tried several times until it finally worked!

This is what I tried:
- After a back-up of all my 'Live Pages', I restored the CP88 to factory settings.
- I tried with different USB-sticks. With one model it was erratically; sometimes the CP88 saw it, sometimes not. I was even able to perform a back-up to the stick, but the CP88 was unable to find it afterwards.
- Format the USB-stick on the CP88. This is very important.
- Copy the updater file to the USB-stick directly through an USB on the computer! Avoid any HUB.

Afterwards I tried to load my live sets from an USB to restore them on the CP88, and it said "Illegal file".
So again, I formatted the stick on the CP88, then copied the files from my PC avoiding any HUB and finally it worked!
I guess the USB port from the CP88 is the weak point.

I hope it helps and it works for you too.

Same issues with my CP73 firmware update to 1.5 (checksum error). Problem resolved by unzipping the update file 8S89OS_.PGM into the USB directly instead of unzip on my MAC first.