Upgrading to Catalina - Invalid Checksum

[ChickenDenders]

I'm working on upgrading from 10.12.4 to 10.15.7, and running into some trouble.

I've set up a policy utilitzing the Catalina Upgrade script on Github - https://github.com/kc9wwh/macOSUpgrade

My issue is that - the policy will try to download the installer three times, then fail due to a checksum error.

macOS Installer Downloaded 3 Times - Checksum is Not Valid
Prompting user for error and exiting...
0

Now, I don't really care about having this script kick off the other policy to download the installer. I've already got a policy for that, just drops the installer right into /Applications, and it works fine. I've already got it staged on all my computers, ready to kick off once I'm through with testing. I'm just looking for a GO button at this point.

I just want to cut out all this automation for calling another policy to download the installer and verify the checksum, but I don't really know how.

I've seen another poster with the same issue here - https://www.jamf.com/jamf-nation/discussions/35982/macos-upgrade-10-15-checksum-not-valid

Tried the steps others have suggested, commenting out the checksum calls and setting checksumvalid=1 values where appropriate.

How can I just skip all that stuff and call upon the installer to RUN? I'm trying to find a more simplified deployment method but everything just keeps pointing back to this same script.
Thanks folks --

[ChickenDenders]

Update - Shortly after posting this, I found that if I set the $4 variable to /Applications/Install macOS Catalina.app IN THE SCRIPT instead of as parameter through the JAMF script options, it finally recognized my pre-staged installer instead of trying to redownload it ;)

## Specify path to OS installer – Use Parameter 4 in the JSS, or specify here.
## Parameter Label: Path to the macOS installer
## Example: /Applications/Install macOS High Sierra.app
OSInstaller="/Applications/Install macOS Catalina.app"

Sorry if my above post came off as ranting - because I absolutely was. Hopefully this helps someone as frustrated as I was!

[ChickenDenders]

Update -

Computer has been sitting for an hour on the "Preparing for Catalina Update" screen, which should apparently only take 5-10 minutes... Hoo boy this sure is fun. Back to the drawing board.

[ChickenDenders · Accepted solution]

Eventually this article brought me to victory. I was not setting my script to kick off "Before" in my deployment policy. And I did not set the parameters in every possible place as listed in the article. Maybe it'll help somebody else.

https://hcsonline.com/images/PDFs/Upgrade_Catalina_Jamf.pdf